Attachment 1 

RELEVANT PASSAGES FROM SECTIONS 112(d), 112(h) and 302 

Section 112(d) 

(d) Emission standards 

(1) In general 

The Administrator shall promulgate regulations establishing emission standards 

for each category or subcategory of major sources and area sources of hazardous air 

pollutants listed for regulation pursuant to subsection (c) of this section in accordance 

with the schedules provided in subsections (c) and (e) of this section. The Administrator 

may distinguish among classes, types, and sizes of sources within a category or 

subcategory in establishing such standards except that, there shall be no delay in the 

compliance date for any standard applicable to any source under subsection (i) of this 

section as the result of the authority provided by this sentence. 

(2) Standards and methods 

Emissions standards promulgated under this subsection and applicable to new or 

existing sources of hazardous air pollutants shall require the maximum degree of 

reduction in emissions of the hazardous air pollutants subject to this section (including a 

prohibition on such emissions, where achievable) that the Administrator, taking into 

consideration the cost of achieving such emission reduction, and any non-air quality 

health and environmental impacts and energy requirements, determines is achievable for 

new or existing sources in the category or subcategory to which such emission standard 

applies, through application of measures, processes, methods, systems or techniques ­

including, but not limited to, measures which ­

(A) reduce the volume of, or eliminate emissions of, such pollutants through 

process changes, substitution of materials or other modifications, 

(B) enclose systems or processes to eliminate emissions, 

(C) collect, capture or treat such pollutants when released from a process, 

stack, storage or fugitive emissions point, 

(D) are design, equipment, work practice, or operational standards (including 

requirements for operator training or certification) as provided in subsection (h) of this 

section, or 

(E) are a combination of the above. 

None ofthe measures described in subparagraphs (A) through (D) shall, consistent with 

the provisions of section 7414(c) of this title, in any way compromise any United States 

patent or United States trademark right, or any confidential business information, or any 

trade secret or any other intellectual property right. 

(3) New and existing sources 
The maximum degree of reduction in emissions that is deemed achievable for new 

sources in a category or subcategory shall not be less stringent then the emission control 

that is achieved in practice by the best controlled similar source, as determined by the 

Administrator. Emission standards promulgated under this subsection for existing 

sources in a category or subcategory may be less stringent than standards for new sources 

in the same category or subcategory but shall not be less stringent, and may be more 

stringent then ­

(A) the average emission limitation achieved by the best performing 12 

percent of the existing sources (for which the Administrator has emissions information), 

excluding those sources that have , within 18 months before the emission standard is 

proposed or within 30 months before such standard is promulgated, whichever is later, 

first achieved a level of emission rate or emission reduction which complies, or would 

comply if the source is not subject to such standard, with the lowest achievable emission 

rate (as defined by section 7501 of this title) applicable to the source category and 

prevailing at the time, in the category or subcategory for categories and subcategories 

with 30 or more sources, or 

(B) the average emission limitation achieved by the best performing 5 sources 

(for which the Administrator has or could reasonably obtain emissions information) in the 

category or subcategory for categories or subcategories with fewer then 30 sources. 

Section 112(h) 

(h) Work practice standards and other requirements 

(1) In general 

For purposes of this section, if it is not feasible in the judgment of the 

Administrator to prescribe or enforce an emission standard for control of a hazardous air 

pollutant or pollutants, the Administrator may, in lieu thereof, promulgate a design, 

equipment, work practice, or operational standard, or combination thereof, which in the 

Administrator's judgment is consistent with the provisions of subsection (d) or (f) of this 

section. In the event the Administrator promulgates a design or equipment standard 

under this subsection, the Administrator shall include as part of such standard such 

requirements as will assure the proper operation and maintenance of any such element of 

design or equipment. 

(2) Definition 

For the purpose of this subsection, the phrase "not feasible to prescribe or enforce 

an emission standard" means any situation in which the Administrator determines that ­

(A) a hazardous air pollutant or pollutants cannot be emitted through a 

conveyance designed and constructed to emit or capture such pollutant, or that any 

2 
requirement for, or use of, such a conveyance would be inconsistent with any Federal, 

State or local law, or 

(B) the application of measurement methodology to a particular class of 

sources is not practicable due to technological and economic limitations. 

Section 302(k) 

(k) The terms "emission limitation" and "emission standard" mean a requirement 

established by the State or the Administrator which limits the quantity, rate, or 

concentration of emissions of air pollutants on a continuous basis, including any 

requirement relating to the operation or maintenance of a source to assure continuous 

emission reduction, and any design, equipment, work practice or operational standard 

promulgated under this chapter. 

3 
ENVIRON 

August 23, 2010 

Via Electronic Submission (in PDF) 

U.S. Environmental Protection Agency 

EPA Docket Center 

Mailcode: 2822T 

1200 Pennsylvania Ave., NW., 

Washington, DC 20460 

a-and-rdocket@epa.gov 

Re:	 Docket 10: EPA-HQ-OAR-2002-0058"- -;'(09. { 

Docket 10: EPA-HQ-OAR-2006-0790 

Dear Administrator Jackson: 

I appreciate the opportunity to comment on EPA's proposed National Emission Standards for 

Hazardous Air Pollutants for Industrial, Commercial and Institutional Boilers and Process 

Heaters located at major and area sources , at 75 FR 32006 and 31896, respectively (June 4, 

2010). I have spent a large part of my 30+ year career involved in the measurement and 

evaluation of criteria, hazardous and other air pollutant emissions from boilers and process 

heaters. My experience includes many field test programs on behalf of industry and EPA to 

develop data for use in rulemaking and regulatory processes, and research and development 

programs to understand and control emissions from combustion processes. My brief comments 

given on the following pages relate to the technical infeasibility of measuring several of the 

proposed emission limits. 

Sincerely, 

~£J~ Glenn C. England 

Principal Consultant 

docum ent1 

18100 Von Karman Avenue, Suite 600, Irvine, CA 92612 VNIW.environcorp.com 

Tel: +1949.261.5151 Fax: +1 949.261.6202 
G. England comments on proposed boiler and heater NESHAP August 23, 2.010 

2
 

COMMENTS ON PROPOSED RULE FOR INDUSTRIAL, COMMERCIAL AND INSTIUTIONAL 

BOILERS AND PROCESS HEATERS LOCATED AT MAJOR AND AREA SOURCES 

75 FR 32006 (Docket ID: EPA-HQ-OAR-2002-0058) and 75 FR 31896 (Docket ID: EPA-HQOAR-2006-0790) 

Previous studies reported that hazardous air pollutant (HAP) emissions from gas-fired industrial 

boilers and process heaters are typically near or below detection limits of the state-or-the-art 

test methods used to measure them (England et aI., 2001). This also can be seen in emissions 

data provided to EPA for the Boiler MACT Information Collection Request (lCR) . In a significant 

departure from scientific guidelines (Keith et aI., 1983), EPA has used undetected results at the 

reported analytical method detection limits along with detected results to establish MACT floors 

and calculate emission limits for HAPs. Because of the extremely low levels of HAPs present in 

gas-fired boilers and process heaters, many test results are near or below the analytical method 

detection limits. Further, there are additional sources of error beyond the analytical method that 

contribute significantly, often dominantly, to the total uncertainty and overall detection limits of 

stationary source emission test methods. Thus, the contribution of undetected results to 

emission limits for gas-fired boilers and process heaters, and the large uncertainty inherent in 

measurements near these levels, is especially significant. 

1. Because of large uncertainty in lower values, it is inappropriate to use results that are 

less than the limit of quantitation for establishing regulatory limits. EPA should use only 

data that are above the limit of quantitation for the purposes of establishing emission 

limits for HAPs. 

The American Chemical Society Committee on Environmental Improvement, which included 

stakeholders from industry, government and academia, explained the inappropriateness of 

using data below the limit of quantitation in describing underlying scientific principles and 

guidelines for environmental data acquisition and analysis (MacDougal et aI., 1980; Keith et aI., 

1983). EPA has cited such guidelines in its discussion of detection limits for stationary source 

measurements at http://www.epa.gov/ttnemc01/facts.html. 

Measurements at levels near or below method detection limits have larger uncertainty than 

higher levels. In measurement terms, "error" is the difference between a measurement and the 

true value. Uncertainty is a statistically defined metric representing random and systematic ­

errors within a population of measurement data at a given level of confidence - the "fuzziness" 

of a number. As a measurement value approaches zero, the uncertainty or "fuzziness" of that 

value contributed by random error becomes larger. Only when levels reach a value 

considerably above the method detection limit, referred to as the limit of quantitation (LOO), 

does uncertainty fall to acceptable levels. An uncertainty of up to ±30% at the 99% confidence 

level is considered acceptable for environmental measurements. Id. 

A further complication of using results near the lower limit of a method's capability is that the 

definition of detection limit varies widely among reference methods, laboratories and/or stack 

testers, or it is not defined at all. In the absence of uniform definitions and guidance for 

establishing a method detection limit for CO, for example, test reports may include any number 

of different values ranging from the lowest resolution on a digital readout, the lowest digit on a 

spreadsheet, a "comfortable" number rounded up from zero, etc. In its ICR guidance on CO 

measurements, EPA specified that [para.] instrument response should be reported and flagged 

as above detection limit, lncludlnq values less than zero. Any of these values may be below the 

true overall CO detection limit of the test method, yet results are reported and used by EPA in 
G. England comments on proposed boiler and heater NESHAP August23,2010 

3
 

the proposed rulemaking as though they had the same acceptable level of uncertainty as levels 

above the LOa. 

2. The detection limits reported among different source testers and laboratories varies 

substantially. EPA should evaluate detection limits achieved in all tests to assure that 

emission limits are not established below the limit of quantitation that can be routinely 

achieved in practice. 

In the emission test data collected for HCI, mercury and dioxins/furans during the ICR, a very 

wide range of detection limits achieved by different stack testers and laboratories using the 

same EPA test methods is evident (Figures 1, 2, and 3). HCI and mercury detection limits 

span approximately three orders of magnitude, and dioxins/furans TEO detection limits span 

four orders of magnitude. One might point to the specific type of source and potential matrix 

interferences as a source of the variability. Examining the data for HCI and mercury , this does 

not appear likely because the detection limits for clean, gas-fired sources span almost the same 

range as detection limits for all fuels including coal, biomass and liquids. This wide range of 

method performance is an indication of reproducibility among different testers, even though the 

same test methods were used in almost all cases. 

This provides an indication of the significance of factors beyond the analytical method detection 

limit. These test methods were originally developed for measuring emissions from waste 

incinerators at concentrations several orders of magnitude higher than gas-fired sources . While 

the methods may perform sufficiently well in those applications, these results indicate the 

processes in the test methods are not sufficiently well controlled for reliable measurements near 

the method detection limits. 

EPA should not set emission limits lower than the limit of quantitation that can be routinely _ 

achieved in practice by most source testers and laboratories. For example , a 99% upper 

prediction limit (UPL) could be calculated using all of the detection limits reported in EPA's 

database , and this could be used to establish an alternative measurement performance based 

minimum limit that can be measured routinely in practice. The detection limit data used for 

establish ing the alternative measurement performance based minimum limit need not be limited 

to data in the MACT floor because there is no requirement for EPA to establish limits that can 

only be measured by the top source testers and laboratories on an occasional good day. 

Instead, EPA must set limits for which measurements are technically feasible. 

An example calculation of an alternative minimum emission limit using the same methodology 

that EPA used for establishing proposed MACT emission limits is shown in Table 1. Neglecting 

the outliers apparent in Figure 2, there are 304 detection limits reported for undetected mercury 

results. The 99% UPL of these detection limits is 3.7E-06 Ib/MMBtu. The corresponding limit of 

quantitation would be 10/3 times this (Keith et aI., 1983), or 1.2 E-05Ib/MMBtu. This represents 

an alternative mercury emission limit that could be measured above the detection limits 99% of 

the time in a 3-run future test by any test team and laboratory. All of the proposed mercury 

emission limits are less than level. 

EPA's proposed emission limit for Gas 2 equates to a concentration of few parts per billion. ­

Using the same approach for HCI (Table 2), an alternative method performance based minimum 

limit of 0.005Ib/MMBtu, or approximately 5 ppm of HC!. Based on this approach, the proposed 

Gas 2 emission limit appears to be technically infeasible from a measurement perspective. 

The 99% UPL of the reported detection limits is a very conservative indicator of method 

performance - perhaps overly conservative. Other metrics may be considered. However, in 

any event EPA fully consider and understand the disparity in measurement performance 
G. England comments on proposed boiler and heater NESHAP August 23, 2010 

4
 

indicated in EPA's database before establishing emission limits that are near or below detection 

limits. 

3. EPA should re-assess test method performance capabilities at low concentrations and 

revise the proposed emission limits to assure that they are not less than the limit of 

qu antitation for their respective measurement methods. 

Many of the proposed performance test methods for demonstrating compliance with the 

proposed emission limits were conceived, developed and evaluated in the 1980's and 1990's for 

application to waste incinerators, municipal waste combustors and coal-fired boilers. They have 

not been similarly evaluated for concentrations as low as many of the proposed emission limits . 

The fact that a method produces a number does not necessarily mean that number is a reliable 

indication of the true value. The range of detection limits reported in EPA's database indicates 

the need for a full evaluation of method performance at low concentrations, including precision, 

accuracy and reproducibility. 

T ble 1 E a xamp e es irna Ion f r 0 f 99% UPL 0 for mercury de ec Ion t r rrrruits.

Mercury (excluding high/low outliers) Normal LNNormal 

Number of Points 304 304 

Average 1.25E-06 -1.44E+01 

Standard Deviation 1.71E-06 1.37E+00 

Skewness 3.24 -0.37 

Kurtosis 14.53 -0.26 

SE Skewness 0.14 0.14 

SkewnessTest Not Normal Normal 

SE Kurtosis 0.28 0.28 

Kurtosis Test Not Normal Normal 

99% t-Statistic for UPL 2.34E+00 2.34E+00 

99% UPL (Detection limits) 3.6E-06 3.7E-06 

LOQ 1.2E-05 
G. England comments on proposed boiler and heater NESHAP August 23, 2010 

5 

Table 2. Example estimation of 99% UPL for HCI detection limits. 

Hel (excluding high/ low outliersl Normal 

LNNormal 

Num ber of Points 118 118 

Average 5.67E-04 -8.32E+00 

Standard Deviation 9.12E-04 1.36E+00 

Skewness 3.32 -0.15 

Kurtosis 11.89 -0.20 

SE Skewness 0.23 0.23 

Skewness Test Not Normal Normal 

SE Kurtosis 0.45 0.45 

Kurtosis Test Not Normal Normal 

99% t-Statistic for UPL 2.36E+OO 2.36E+OO 

99% UPL (Detection Limits) 1.8E-03 1.6E-03 

LOQ 5.3E-03 

References 

England, G.C., McGrath, T.P., Gilmer, L" Seebold, J.G., Lev-On, M., Hunt, T. Hazardous air 

pollutant emissions from gas-fired combustion sources: emissions and the effects of design and 

fuel type, Chernosphere 42 (2001) 745-764 . 

MacDougal, D. et. AI. Guidelines for Data Acquisition and Data Quality Evaluation in 

Environmental chemistry. Anal. Chern. 1980, 52, 14, 2242-2249. 

Keith, L.H., Crummet, W., Deegan, J., Libby, R.A., Taylor, J.K. and Wentler, G. Principles of 

Environmental Analysis, Anal. Chern. 1983, 55, 2210-2218. 
G. England comments on proposed boiler and heater NESHAP August 23, 2010 

6
 

1.00E-01 - ---- -..- ---.- -..- .-- - .-.- -- - - - -- -- - - -...-.-...-- -- - ..- - - - .- - - .-...- --.-- -- - ----------- ---- ­

1.00E-02 

iii I 

1_ _ - -:11.--- --

__ HCI- all ::;; 

1.00E-03 --- -------:j -- ..... HCI- Gas 1 & 2 E 

iJ - Gas 199%UPL :I: 

- Gas 21imit 

1.00E-04 

1.00E-05 

1.00E-06 

, 1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97101105109113117121 

L.. _ - - - - - 1 

Figure 1. HCI detection limits reported in Boiler MACT ICR database version 5 compared to 

proposed emission limit for Gas 2 and prospective limit for Gas 1 fuels. 
- - --------- - - ---- -- - ----

G. England comments on proposed boiler and heater NESHAP August 23, 2D1 0 

7 

.;;" 0 .0000001 :;;: 

:;;: 

. 

H..-- -:::II.--'---	

__ Hg-all 
 


 ....... Hg -Gas 1 & 2
 

1E-0 8 . - - _ . .........-_ _ __ _ - --_.._ ..__.__._ _ .._ - Gas··l ·.99% UPL & Gas 2 Limit
 

1E-09 _ .._ _.._..__ _-_ - - _ - .._ _ - _ _ .• .- - _ -._._._ . 

1 E-1O JIo------- - ------- - ----- --- -----­

IE-II __ _ _ -_ _ -...•.- - •.. ...............................- _ __ _ - _ .- ._ .- _ ...•.- ..•.- ..•.._ .
 

""" C"l	 ,.... U1 r>"l """ C"I r--, U1 l"f'\ _ C"l " U1 tr'I _ C"l " U1 tr'I 0"'1 C"I " Vl tr'I _ CTI I" If) rr'l 0"'1 CTI I" lJ) rr'l _ m r-- VI rr'l 

.-1 N r>"l 'Of '<t U1 I.D ,.... tXl co O'l a rl N N ffl ..::t Lt'l I.D '-D r-- 00 a'I 0 a """' N r>"l '<t '<t U1 \,[) ,.... tXl co O'l a rl 

...... rl ...-l ...... ...... _ rl...-l..-l._.--I .... NNNNNNNN NNNNNrr"l r>"l 

-- - - --} 

Figure 2. Mercury method detection limits reported in Boiler MACT ICR database vers ion 5 

compared to proposed emission limit for Gas 2 and prospective limit for Gas 1 fuels . 

0 .00001 

0 .000001 ~~~ _._._ ­
------

G. England comments on proposed boiler and heater NESHAP August 23, 2010 

8 

................._ _.._._......._.._.._.._.._..-._._..-.- ..._.._ ._...._--,
 ... ..... 

N 

0.03 N 

0.025 . - --.------- - - - ------..------ --- -.- --- -­

N 

............................................................... ............ . ... ............................. ....· ··..·····_ ·__·_·---N-···¥Jj o
 

: JJ r"': ::; .... 

__ OIFTEO · all 

- Gas 1 99% UPl 

- Gas 2 lim it 

e

"' ';; 

S 0.01 -------- i_-::=~_....------------­

0.00 5 .1-- - ­

10 11 12 13 14 15 16 

'----- ------_._---_._-- - ---_ ._----------_.. _--- - - - - - - ­

Figure 3. Dioxins/furans TEO detection limits (for BDL data only) reported in Boiler MACT ICR 

database version 5 compared to proposed emission limit for Gas 2 and prospective limit for Gas 

1 fuels. 
Attachment 3 

RELEVANT PASSAGES FROM APIINPRA'S COMMENTS 

E-Docket No. EPA-HQ-OAR-2002-0058-2960.1 

(1)	 Argument That EPA Must Determine That There Is Means of Control 

Achieved in Practice within the Category [Pages 64-70.] 

A fundamental issue facing EPA in the present rulemaking is whether Congress intended 

it to set the so-called "floors" for existing and new units within a particular subcategory solely on 

the basis of emissions test data, without regard to whether there is a technically feasible means of 

emissions control in actual usage within the subcategory which is sufficient to achieve the floor. 

EPA squarely addressed this issue in its 2004 Boiler MACT rulemaking, saying: 

Furthermore, setting emission standards on the basis of actual emission 

data alone where facilities have no way of controlling their HAP 

emissions would contravene the plain statutory language as well as 

Congressional intent that affected sources not be forced to shut down. I 

EPA explained: "This is because the statute requires EPA to set standards that are 

duplicable by others.t" Thus, in 2004, EPA interpreted the CAA as requiring it to determine 

when it sets the floors whether there are technically feasible means of compliance in actual usage 

within the subcategory. However, in their challenge to the 2004 Boiler MACT standard before 

the D.C. Circuit, NRDC and the other citizens groups disputed EPA's interpretation, contending 

that EPA must focus only on actual emission rates in setting the floor. 3 EPA vigorously 

defended its view in its responsive brief, saying: " .. . Congress intended EPA to base its 

standards on the amount of emission reduction sources can achieve by the application of some 

form of control, and not on the levels some source may emit simply because of characteristics of 

the source or its operation that cannot be replicated by others.,,4 Moreover, in EPA's view, it has 

a duty to examine the technical feasibility of a floor: " ... Congress did not intend that EPA 

consider just the level of emissions, but rather that the Agency consider how those emission 

levels are achieved and base the standard on the lowest level that can be achieved through the 

implementation ofsome sort ofemission control." !d. (emphasis added). The court, however, 

never decided this issue because it vacated the standard on a different ground.' Thus , EPA must 

face the issue again, in the present rulemaking. 

Unfortunately, EPA on the whole appears in its June 4,2010 proposal to be adoptingwithout an explanatory legal analysis - the position of the citizen groups in the NRDC case. On 

the one hand, EPA acknowledges that "[s]ection 112(d) ... requires [it] to set emission standards 

for [HAPs] emitted by major stationary sources based on the p erformance ofthe maximum 

169 Fed. Reg. 55218,55233 col. 1 (Sep. 13,2004). 

2 Id. 

3 Environment al Petitioners' Initial Opening Brief, at 31 (June 12,2006) (NRDC v. EPA, Case No. 04-1385). 

4 Final Brief for Respondent United States Environmental Protection Agency, at 49 (Dec. 4, 2006). 

5 See NRDC v. EPA, 489 F.3d 1250, 1261 (June 8, 2007). 
achievable control technology (MACT)". 6 [emphasis added]. Also, EPA discusses at length 

whether fuel switching is a technically feasible and hence cognizable form of control within a 

given subcategory of boilers and process heaters.' Thus, EPA shows some sign of adhering to 

its 2004 position. But, on the other hand, EPA appears to have abandoned that position 

inasmuch as it actually calculated its proposed floors solely on the basis of emission levels, 

without making any effort to evaluate whether technically feasible means of achieving those 

levels are in actual use and hence generally available to the units within the subcategory. For 

example, with respect to existing units, EPA stated in the preamble: 

EPA must consider available emissions information to determine the 

MACT floors. For each pollutant, we calculated the MACT floor for a 

subcategory of sources by ranking all the available emissions data from 

units within the subcategory from lowest emissions to highest emissions, 

and then taking the numerical average of the test results from the best 

performing (lowest emitting) 12 percent of sources. 

75 Fed. Reg. at 32019 col. 1. 

With respect to new units, EPA stated: "Similar to the MACT floor process used for 

existing units, the approach for determining the MACT floor must be based on available 

emissions test data ." More to the point, the relevant technical support document confirms that, 

as the preamble implies, EPA in fact based its floor determinations for existing and new units 

solely on the basis of available emissions data, without any examination of whether units have 

some feasible and proven way of achieving the floors." Indeed, the technical support document 

is explicit: 

In response to concern over MACT floor analyses based on control 

technologies, the new approach ranks the performance of each pollutant 

according to the lowest emitting (based on stack test data), regardless of 

control technologies installed on the boiler/process heater. 10 

Thus, EPA appears on the whole to have changed its mind about the methodology 

Congress intended EPA to use in determining the floors for existing and new units, albeit without 

providing any explanatory legal analysis. 

API respectfully urges EPA to return to its 2004 position. The evidence of congressional 

intent strongly and unequivocally shows that Congress intended the regulatory machinery of 

sections 112(d)(1)-(3) to operate so as to: (1) identify those forms of emission control in actual 

use which produce maximum reductions in HAP emissions when applied to particular units; (2) 

6 75 Fed . Reg. at 32008 col. 1
 

7 Id. at 32019.
 

8 Id. at 32027 col. 3.
 

9 See ERG, Mact Floor Analysis (2010) for the Industrial, Conun ercial, and Institutional Boiler and Process Heaters
 

National Emission Standards for Hazardous Air Pollutants - Major Sour ce, at 3, 10 (April 20 I0) (Dock et ID No. 

[INSERT)). 

10 Id. at 3. 

2 
press all existing and new units of the same type from the standpoint of basic production design 

to apply those controls or otherwise achieve at least the same reduced level of emissions, either 

through innovation, reduced operation or some other way; and (3) preserve, protect and enhance 

the economic vitality of the national economy. Thus, in line with other key provisions of the 

Clean Air Act, such as section 111, sections 112(d)(1)-(3) are technology-forcing. They are 

designed to propagate the best HAP emissions control in actual use, not to produce dictates 

achievable only though widespread shutdowns and installation of newly designed production 

equipment. Clearly, to implement that congressional purpose, EPA must base the floors not only 

on available emissions test data, but also on a determination that some technically feasible means 

of achieving the floor is generally available to the units within the subcategory, as demonstrated 

by actual use within the subcategory. Otherwise, if EPA were to base the floors for a particular 

subcategory only on available test data, without examining technical feasibility and actual usage, 

it could produce a MACT standard which a majority - indeed even a plurality - of units in the 

subcategory would have no hope of achieving. That would be a perversion of the congressional 

vision - which is to identify and spread the use of best controls, while preserving economic 

vitality, not to force widespread shutdowns and re-capitalization within industry segments. 

Section 112 is replete with unassailable textual evidence that Congress authorized EPA to 

set a floor only at a level which units within a subcategory generally had some means of 

achieving as a technical matter, as demonstrated by actual usage within the subcategory. In 

implementing section 112, EPA must give full effect to that textual evidence. See Whitman v. 

American Trucking Association, Inc., 531 U.S. 457, 485 (2001) ("The EPA may not construe the 

statute in a way that completely nullifies textually applicable provisions meant to limit its 

discretion."). 

Key pieces of such evidence are as follows: 

•	 Section 112(d)(2), the overarching directive to EPA for establishing a MACT standard 

for any given subcategory, requires EPA to set the standard at a level that corresponds to 

the maximum degree of reduction of HAP emissions that is achievable for the 

subcategory through the "application of measures, processes, methods, systems, or 

techniques". (Emphasis added.) Sections 112(d)(2)(A)-(E) then define those various 

forms of emissions control as including a wide range of "measures". Specifically listed 

are process changes, materials substitution, enclosures, add-on control technology, work 

practices, and operational standards. Not listed, or even suggested, were changes to the 

basic design of the units in question, the HAP-emitting production equipment. Section 

112(d)(2) thus reflects and reveals a fundamental conceptual orientation on the part of 

Congress which is universal to all of the technology-based standard-setting processes 

dictated by the CAA. In crafting the MACT standard setting process, Congress took 

production equipment, such as boilers and process heaters , as a given and envisioned that 

the standards EPA generated would stimulate the "application" of control "measures" to 

the production equipment, without change to the basic design of the equipment. In other (	 

words, section 112(d)(2) evidences a fundamental mindset on the part of Congress, 

namely: Congress sought to control HAP emissions by forcing investments only in 

control measures. It did not seek to control HAP emissions by dictating or restricting 

basic designs of production equipment. Congress left individual companies free to make 

3 
fundamental decisions about their core capital investments, especially the basic design of 

production equipment. 

•	 Section l12(d)(3)(A) is also an expression of, and hence reveals, that mindset. It calls on 

EPA to set the floor for existing units within a subcategory at the average level actually 

"achieved" by the best "performing" 12 percent. The use of the terms "achieved" and 

"performing" imply that Congress had in mind a cause-and-effect relationship between 

the actual in-use application of one or more of the control measures listed in section 

l12(d)(2)(A)-(E) to a piece of HAP-emitting equipment and a resulting actual level of 

reduced emissions from the equipment. The terms indicate that Congress distinguished 

between such measures and the fundamental design of the equipment and wanted to 

identify those measures by which EPA could reliably establish norms of behavior for 

pieces of equipment of like design. In other words, Congress sought to spread the use of 

those controls proven to be best by actual practice, but not force changes in the 

fundamental design of production equipment within an industry segment, e.g., through 

shutdowns and re-capitalization. If EPA, however, were to base the floor for existing 

units within a subcategory only on average emissions test data, without examining the 

cause-and-effect relationships, it could end up setting a floor which would operate t-o 

force changes in fundamental design of production equipment. That would be contrary to 

the textual thrust of section 112(d)(3)(A), especially in the light of the fundamental 

structure of section 112(a)(2), as EPA recognized in the first Boiler MACT rulemaking. 

In short, Congress authorized EPA to set behavioral norms only for the application of 

proven best controls to existing HAP-emitting equipment within an industry segment. It 

did not authorize EPA to set norms for the basic design of such equipment. 

•	 The first sentence of section 112(d)(3), which specifies the methodology EPA must 

follow to set a floor for new units, carries the same meaning. It provides: "The 

maximum degree of reduction in emissions that is deemed achievable for new sources in 

a category or subcategory shall not be less stringent than the emission control that is 

achieved in practice by the best controlled similar source ...." Once again, the phrases 

"reduction in emissions", "achieved in practice", and "best controlled" all bring to mind, 

especially in juxtaposition with section l12(d)(2), the application of control measures to 

HAP-emitting production equipment. The first sentence of section 112(d)(3) thus 

confirms that Congress regarded the basic design of such equipment as a given andsought to identify the forms of control that experience showed to be the most effective 

and that companies could apply in a replicable way without altering the basic design of 

the production equipment. 

•	 Section lI2(d)(6) also reflects this mindset. It requires EPA to "review, and revise as 

necess ary (taking into account developments in practices, processes, and control 

technologies), emission standards promulgated under this section no less often than every 

8 years ." The reference to "practices, processes, and control technologies" indicates what 

Congress regarded as factors of significance in setting behavioral norms for controlling 

HAP emissions. In the light of section 112(d)(2)(A)-(E), those factors are limited to 

means of control applicable to an already established basic design of the relevant piece of 

4 
productive equipment. Section l12(d)(6) thus confirms that Congress did not intend to 

authorize section 112(d) standards that could constrain the choice of such basic design . 

Other provisions of the CAA provide further evidence of Congress ' intent. First, several 

provisions other than section 112 call for the establishment of technology-based emission 

standards for stationary sources, namely: section 111 (New Source Performance Standards 

(NSPS)), section 129 (incinerators), section 165 (Best Available Control Technology (BACT) 

for certain new construction projects), section 172(c)(l) (Reasonably Available Control 

Technology (RACT) for existing sources as control by State Implementation Plans), and section 

173 (Lowest Achievable Emission Rate (LAER) for certain new construction projects). In each 

case, the basic idea is to set a behavioral norm based on the application of available and 

"demonstrated" control technology, without fundamentally compromising the freedom of 

companies to choose the basic design of their production equipment. There is no sign in the 

CAA that Congress intended section 112(d) to operate differently or to authorize EPA in setting 

MACT standards to encroach fundamentally on that basic freedom. Second, section 101(b)(1) 

declares that an overarching purpose of the entire CAA is "to protect and enhance the quality of 

the Nation 's air resources so as to promote the public health and welfare and the productive 

capacity ofits population." [Emphasis added.] If EPA were to set floors under section 112 

solely on the basis of emission rates, without regard to the cause-and-effect relationship between 

available proven controls and such rates, inevitably it would defeat that purpose by severely 

compromising the Nation's productive capacity. 

The legislative history of section 112 confirms that Congress was aiming to identify and 

spread best, in-use-proven controls of HAP emissions within the appropriate categories and 

subcategories of HAP-emitting equipment, without fundamentally constraining the ability of 

companies to choose the basic design of that equipment. During the Senate debates on the 

conference bill that became the CAA Amendments of 1990, Senator Durenberger, the primary 

author of section 112, stated: "For each category of sources, EPA will promulgate a standard 

which requires the installation of maximum achievable control technology (MACT) by the 

sources in the category."l! Later in the same debates, Senator Chafee, one ofthe managers ofthe 

legislation, echoed Senator Durenberger's description.f Still later, Senator Baucus, another 

manager of the legislation, stated: 

Mr. President, the MACT requirement is the cornerstone of this approach. It 

means that the source may need to install a scrubber, selective catalytic reduction, 

adjust the combustion temperature of its equipment, substitute materials or apply other 

methods to reduce air emissions.i'' 

Plainly, in their mind, section 112(d)(1)-(3) would cause companies to take action only to 

apply controls to an established equipment design, as opposed to cause changes in such design. 

If EPA were to set the floors solely on the basis of emissions test data, without examining the 

II Committee on Environment and Public Works, U.S. Senate, Legislative History ofthe Clean Air Act Amendments 

of1990, S. Prt. 103-38, at 863 (Nov. 1993). 

12 [d. at 951. 

13 [d. at 1029. 

5 
technical reasons for the actual emission level, it could end up setting a standard that a company 

could achieve only by mixtures of shutdowns and shifts in basic design of production equipment, 

as opposed to the application of control measures. Thus, EPA would fail to keep faith with the 

intent of Congress. 

Finally, no court decision has addressed squarely whether EPA may set a floor solely on 

the basis of emissions test data, without regard to the existence of a proven means of achieving 

the floor. The D.C. Circuit in the Brick MACT case, Sierra Club v. EPA, 479 F.3d 875 (2007) , 

did not address that issue squarely. As characterized by EPA in the June 20 I0 proposal, the 

closest the court came to addressing that issue was to rule that "[fJloors for existing sources must 

reflect the average emission limitation achieved by the best-performing 12 percent of existing 

sources, not levels EPA considers to be achievable by all sources.,,14 [emphasis added]. That is 

a different issue. An individual source within a particular subcategory may not be able to 

achieve a floor because of cost, even if a proven means of control is available to it from a 

technological standpoint. 

As shown above, Congress did not authorize EPA to set a floor on the basis of emissions 

test data, without also determining that there are technologically feasible means of achieving that 

floor which actual usage within the subcategory has shown are available to all of the units in the 

subcategory given their particular basic design. If EPA were to determine that there are no-such 

means of control across the subcategory, it would have to subcategorize further in order to group 

units of like design or, if that were not practicable, base the ultimate standard on a universally 

applicable work practice, such as annual tune-ups, as EPA has proposed here in the case of Gas I 

units. 

(2) Argument on Work Practice Standard. [Pages 34-36.] 

EPA proposes to establish as the emissions standard for existing and new boilers and 

process heaters that combust natural gas or refinery gas (Gas 1) a work practice consisting of 

annual tune-ups. EPA gives two reasons in support of this stance'f. 

First, EPA estimates that the cost of compliance with emission limits would be exorbitant 

- $14 billion - because compliance would require the widespread installation of a system of 

combined fabric filter and wet scrubber technology. Indeed, the database does not show any Gas 

1 unit whatsoever currently employs such technology. 

Second, that cost would create perverse incentives which could result in more HAP 

emissions than would otherwise occur. For example, a company with a solid fuel-fired boiler 

might be deterred from switching to a natural gas-fired boiler; and a company with a natural gasfired boiler might be encouraged to switch to a solid fuel-fired boiler. 

At the same time, EPA solicited comment on specifically how it could justify the use of 

its authorities under section 112(h) to set a work practice standard. It also solicited comment on 

14 75 Fed. Reg. at 32009-10
 

15 See 75 Fed. Reg. at 32025 cots. 2-3, 32029.
 

6 
whether, instead of requiring the tune-up work practice, it should adopt the numerical emission 

limits for existing and new units it specified in Table 4 of the preamble'". We comment on the 

latter point in Section VI ofthese comments. 

API/NPRA strongly support EPA's proposal to establish annual tune-ups as the MACT 

standard for existing and new Gas I boilers and process heaters , with the revisions in the details 

of the work practice discussed below, and respectfully urges EPA to adopt that proposal in final 

form, rejecting any comments urging the adoption of numerical emission limits, such as those as 

to which EPA solicited comment. In thus adopting annual tune-ups as MACT, EPA should 

recognize expressly that they constitute the floor for existing and new Gas I boilers and process 

heaters and that no beyond-the-floor requirement would be appropriate for the reasons EPA gave 

in support of its proposal, namely: the exorbitant cost of compliance and the perverse incentives . 

Even if EPA is able to calculate an emissions rate that reflects the performance ofthe 

lowest-emitting unit or units within the Gas I subcategory, EPA still must examine its database 

to determine whether it reveals any in-use control measure that would be technologically 

available to all of the units in the subcategory and generally sufficient for them to achieve the 

identified emissions rate, putting aside costs. If EPA cannot identify such a control measure, it 

may not translate the emissions rate into a standard, because it would then be interfering with 

fundamental choices about the basic design of production equipment. Instead, EPA must 

subcategorize further or, if that is not possible, search under the authority of section 112(d){2) for 

any measure that has been shown to work in practice to reduce HAP emissions and is generally 

technologically feasible within the subcategory. Such a measure would constitute the "floor." 

For the gas-fired boiler and process heater subcategories, it is not possible to discern in 

the Gas I database any control measure whatsoever through which the plurality of units in the 

Gas I subcategory could reach the emissions level of the lowest-emitter(s). To the contrary, the 

database shows that the primary explanation for the differences in emissions rates is the 

differentials in the design and operating char acteristics of the Gas I units and the inherent 

variability of the fuel. In these circumstances, EPA is not authorized to set the MACT standard 

in line with the emissions of the lowest emitters and must abandon the attempt. 

It is not possible, in this case, for EPA to subcategorize further on the basis of design or 

operating characteristics and then apply the floor methodologies in section 112(d)(3) to derive 

numerical emission limits for appropriate sub-grouping of Gas I units. The Gas I database lacks 

sufficient information to allow rational sub-grouping of all of the Gas I units. In addition, the 

database lacks sufficiently robust emissions data to allow the calculation of floors for each of the 

resulting sub-groups. As we have discussed elsewhere, we do not feel the database information 

is even adequate for allowing emission limits to be calculated for the subcategories 

recommended in the proposal much less for SUb-groupings of those subcategories. 

Since it is not possible for EPA to set floors for Gas I units under section 112(d)(3), EPA 

is relegated necessarily to section 112(d)(2) , which calls for a search through the database for 

any efficacious form of control in significant actual usage. The only such control measure.that 

16 [d. at 32025 col. 3, 32029 col. 3. 

7 
can be discerned in the data available is tune-ups. Thus, tune-ups constitute the de facto "floor" 

for existing and new units. 

EPA then must determine under section II2(d)(2) whether there are "beyond the floor" 

measures, e.g., demonstrated technologies not in significant actual use within the Gas I 

subcategory, which could serve as a basis for a more stringent MACT standard. EPA then must 

determine whether the use of such measures would be "achievable", taking into account costs of 

control, non-air quality health and environmental impacts, and energy requirements. 

Here, there are such measures, i.e., a system combining fabric filter and wet scrubber 

technology. But they are not "achievable" because of the exorbitant cost and perverse incentives 

which EPA outlined in its proposal. Thus, the heart of EPA's rationale for its tune-up proposal is 

actually a traditional "beyond the floor" analysis. 

Finally, EPA must set a standard for HAPS from Gas I units, reflecting the application of 

tune-ups. Here, however, no single numerical standard is technically feasible. The design 

characteristics of the units and, hence the emissions-reduction potentials of annual tune-ups, vary 

widely. Consequently, there is no single emission rate or even percentage of emission reduction 

that could be translated into a numerical limit. EPA has no choice but to set a work practice 

standard. 

EPA has ample authority to set the standard for Gas I units in terms of a work practice. 

First, section II2(d)(1) authorizes - indeed requires - EPA to set "emission standards" for each 

category or subcategory, and section 302(k) defines "emission standard" to include work practice 

standards. Second, section 112(h) independently authorizes EPA to use a work practice standard 

in two situations. The first [section II2(h)(2)(A)] is where the emissions are not susceptible to 

control after the underlying source generates them, as is the case with fugitive emissions (e.g., 

emissions from demolition). Here, tune-ups arguably fit that situation because they operate to 

minimize emissions, rather than reduce them after the source generates them. The second 

situation is where the application of a system for measuring the effect of the control measure for 

enforcement purposes is not practicable. 

(3) Argument on Rationality. [Pages 54-55.] 

In making the determinations required by section II2(d), e.g., determinations as to the 

emission rates which represent the technological "floor" for new or existing units, EPA must 

satisfy basic requirements of rational decision-making. Congress explicitly consigned to the 

federal courts of appeals, and in particular the D.C. Circuit in the case of section II2(d) 

standards, the job of reviewing EPA's final actions upon petition and overturning them for 

failure to satisfy those rationality requirements. 17 Thus, rationality principles constitute a 

fundamental underpinning of section 112(d), notwithstanding the formulaic nature of section 

II2(d)(3). To survive judicial review, a MACT standard must be based demonstrably on rational 

decision-making. 

17 See CAA § 307(d)((9), 42 U.S.c. § 7607(d)(9). 

8 
In reviewing EPA 's actions under the CAA generally, the D.C. Circuit has firmly 

embraced that interpretation of the Act in many opinions. A much-quoted passage is the 

following one : 

We will not set aside a final rule under the Clean Air Act unless the 

underlying agency action was "arbitrary, capricious, an abuse of 

discretion, or otherwise not in accordance with law" or "in excess of 

statutory jurisdiction, authority, or limitations, or short of statutory 

right." 42 o.s.c. § 7607(d)(9)(A) & (C). The "arbitrary and 

capricious" standard deems the agency action presumptively valid 

provided the action meets a minimum rationality standard. See, 

e.g., Small Refiner Lead Phase-Down Task Force v. EPA, 227 Us. App. 

D.C. 201, 705 F.2d 506, 520-21 (D.C. Cir. 1983). In applying this 

standard we determine whether the agency has considered the relevant 

factors and articulated a rational connection between the facts and its 

choices. See Motor Vehicle Mfrs. Ass 'n ofthe United States v. State 

Farm Mut. Auto. Ins. Co., 463 Us. 29, 43, 77 L. Ed. 2d 443, 103 S. Ct. 

2856 (1983). While we carefully review the factual record, we will give 

due deference to the agency especially when the agency action involves 

evaluating complex scientific or statistical data within the agency's 

expertise. See Ethyl Corp. v. EPA, 176 Us. App. D.C. 373, 541 F.2d 1, 

34-36 (D.C. Cir. 19 76) (en bane). [Emphasis added in bold] 

NRDC v. EPA, 194 F.3d 130, 136 (D.C. Cir. 1999). 

In a case arising under section 112(d), then Judge Roberts, now ChiefJustice ofthe U.S. 

Supreme Court, quoted with approval the sentence highlighted in bold print in the above 

quotation, clearly intending to apply the rationality principle to the MACT standards at issue in . I 18 t at h particu ar case. 

Indeed, in leading cases involving section 112(d), or its mirror-image counterpart, section 

129(a)(2), 42 U.S.C. § 7429(a)(2), the D.C. Circuit has upheld, elaborated on and applied the 

rationality principle repeatedly. A prime example is Cement Kiln Recycling Coalition v. EPA, 

255 F.3d 855 (2001), where the court stated : 

In Sierra Club, we held that CAA section [129(a)(2)] ... requires EPA 

to make a reasonable estimate of the performance of the top 12 percent of 

units. While acknowledging that EPA has authority to devise the means 

of deriving this estimate, we made clear that the method EPA selects 

must allow a reasonable inference as to the performance of the top 12 

percent of units. We emphasized that EPA must show not only that it 

believes its methodology provides an accurate picture of the relevant 

sources' actual performance, but also why its methodology yields the 

required estimate .... In National Lime II, we addressed a Sierra Club 

18 See Sierra Club v. EPA, 353 F.3d 976 , 978 (D.C. Cir. 2004). 

9 
petition challenging emission standards set under section [112( d)] for 

non-hazardous waste-burning Portland cement kilns. In evaluating 

EPA's standards, we reiterated Sierra Club's central holding that to 

comply with the statute, EPA's method of setting emission floors must 

reasonably estimate the performance of the relevant best performing 

plants. 

Id. at 861-62 (emphasis added in bold; citations and quotation marks omitted). Evidently, in the 

court's view, a "floor" determination is rational only if it accurately reflects actual performance. 

Here, it would be the antithesis of rationality for EPA to base a section 1l2(d) 

determination on data that is unrepresentative of actual reality. Such data simply cannot depict 

actual performance accurately. That would be arbitrary and capricious, and the D.C. Circuit 

would strike down any MACT standard based on such a determination. 

[END] 

10 
KEY LEGAL POINTS 

Comments ofAP/INPRA on EPA's Proposed MACT Standards 

for Gas-Fired Boilers and Process Heat ers 

A. Background 

• Gas-fired boilers and process heaters ("boilers") vary greatly in size, design 

and typical usage , so that HAP emissions vary as well. Emission data from 

boilers at one end of the spectrum cannot possibly be representative of 

emissions from units at the other end. 

• The database EPA has gathered indicates that emissions of HAPs from gasfired boilers are very small, often at or below limits of detection and generally 

below the "limit of quantitation" ("LOQ"), the lowest level of emissions at 

which current measurement technology can generate reliable results . (See the 

attached comments from Glenn England .) 

• The only form of control discernible in EPA's database for gas-fired boilers is 

good combustion practices, notably tune-ups. Consequently, EPA 's proposed 

work practice standard requiring tune-ups for boilers burning natural gas or 

refinery gas ("Gas-I") is sensible and required by the Act, as explained below. 

Such a standard should govern boilers burning chemical process gas as well. 

A tune-up provides for the optimal reduction of all pollutants by operating the 

boiler in an energy efficient manner. This efficient operation minimizes thefuel input into the boiler and consequently minimizes the emissions of 

pollutants. 

• EPA proposed numeric limits for gas-fired boilers. They were calculated on 

the basis of the lowest emissions levels in its database, without regard to 

whether there are technically feasible means of emissions control in actual 

usage within the category which are sufficient to achieve the limits. 

• Compliance with the proposed limits would require, if compliance is possible 

at all, the installation of an activated carbon injection system, a fabric filter 

system, a wet gas scrubber, and an oxidation catalyst. None of the first three 

forms of control are in usage within the gas-fired boiler subcategory. 

Certainly, there is not a single gas-fired boiler that has all four in actual usage. 

• As EPA recognized, the cost of such installation would be enormous, yet the 

emissions reductions tiny. The cost is so great it could cause widespread . 

mothballing and shutdown of gas-fired boilers or entire plants, and shifts to 

solid-fuel fired boilers. It would interfere greatly with the business decisions 

companies make about their investments in sources of power. 

• The lowest emission levels in the database reflect the basic design of the 

boilers at one end of the vast design spectrum of boilers, as opposed to the 
application of control technology. Thus, thousands of boilers of different 

designs would be expected to conform to the emissions performance of a few 

basic designs, even though none of the boilers in the spectrum use the control 

technologies necessary for compliance. 

•	 We cannot believe that Congress intended this. In our view, Congre ss 

designed section II2(d) to identify the best form of HAP control in actual use 

within a category and then to force the spread of that technology within the 

category. 

•	 Here, the only discernible form of control among gas-fired boilers is tune-ups. 

Thus , we support adoption of the work practice standard for gas-fired boilers, 

not the numeric standards. 

c.	 Legal Point: A Work Practice Standard for Gas-Fired Boilers Is Fully 

Authorized by Section 112(h). 

•	 Section II2(h)(2)(B) authorizes the use of a work practice standard whenever 

"the application of measurement methodology to a particular class of sources 

is not practicable due to technological and economic limitations." 

•	 Per the attached paper by G. England, the use of current measurement 

methodology to show compliance with the extremely low numerical limits 

proposed by EPA for gas-fired units is not practicable. That methodology is 

not capable of reliably measuring emissions levels as low as those limits 

because they are below the LOQ. 

D.	 Legal Point: A Work Practice Standard for Gas-Fired Boilers Is 

Authorized and Required by Section 112(d). 

•	 Section lI2(d) requires EPA to set the MACT floors not only on the basis of 

available emission data, but also on a determination that there is some 

technically feasible means of control in actual usage within the subcategory 

that is sufficient to achieve the floor. There must be some pathway to 

compliance that is discernible in the database for the subcategory. 

•	 First, the terms "achieved," "controlled," and "performing" in section 

lI2(d)(3) strongly imply that Congress had in mind a cause-and-effect 

relationship between the actual in-use application of some form of control to a 

piece of equipment and the resulting actual level of reduced emissions. 

•	 But more important is a fundamental mindset. Congress took production 

equipment, such as boilers, as a given and envisioned that the MACT 

standards EPA generated would require the application of controls to such 

equipment, without change to the basic design of the equipment. 

2 
•	 Congress was aiming through section II2(d) to identify best forms of control 

used in practice within a category and to force the spread of that technology 

within the category. It wanted to control HAP emissions by forcing 

investments in control measures, not by dictating or restricting basic designs 

of control equipment. 

•	 To be faithful to that mindset, EPA cannot base its "floor" determination only 

on available emissions data. It must also examine whether the units in the 

category have a compliance pathway available to them consisting of controls 

that have been shown to be feasible and effective in practice for the category. 

Otherwise, EPA could produce a MACT standard that would force all units to 

apply controls that no single unit ever employed or else abandon the 

equipment and invest in other forms of production. 

•	 There is no D.C. Circuit ruling to the contrary. 

•	 EPA ordinarily would set the floor at a numeric level which units within the 

subcategory generally have some means of achieving, as demonstrated by 

actual usage within the subcategory. If that is not possible, EPA would set a 

work practice standard. Section 112(d)(l) gives EPA authority to do that. It 

requires EPA to set "emission standards," and section 302(k) defines 

"emission standard" as including work practice standards. Section 112(h) is 

not an exclusive source of authority for setting such standards. 

•	 Here, by focusing blindly only on emissions data, EPA is proposing to force 

gas-fired boilers to apply add-on controls such as fabric filter and wet 

scrubber technology, even though not a single gas-fired boiler in the data isusing such add-on controls. The consequence would be a movement away 

from the use of gas-fired boilers in one form or another. 

•	 The only fonn of control used in practice that is discernible in EPA's database 

for gas-fired units is tune-ups. EPA therefore has no choice but to set the 

MACT standard to require tune-ups. However, there is no single numerical 

limit that reflects the application oftune-ups to the entire range of gas-fired 

boilers. EPA therefore has no choice but to set a work practice standard. 

E.	 Conclusion: EPA should adopt the proposed work practice standard for gas-fired 

boilers. 

Attachments 

(1) Relevant provisions of sections 112(d), lI2(h), and 302 

(2) Comments submitted by Glenn England 

(3) Relevant passages on legal matters from APIINPRA's comments 

3