Rulemaking for Hazardous Air Pollutants

from Coal- and Oil-Fired Electric Utility

Steam Generating Units

Tribal Consultation 

December, 2010

POC: Eric Ginsburg
Purpose of the Consultation

► Hear from you, your concerns and comments

► Provide background information on EGU’s 

and the history of the rule

► Provide summary of issues we are exploring 

for the proposal

► Discuss your input and comments
Definition of EGU

► The “electric utility steam generating unit” source category includes 

those units that combust coal or oil for the purpose of generating 

electricity for sale and distribution through the national electric grid 

to the public.

► Section 112(a)(8) defines an “electric utility steam generating unit” 

as:

► Any fossil fuel-fired combustion unit of more than 25 megawatts electric 

(Mwe) that serves a generator that produces electricity for sale. A unit 

that cogenerates steam and electricity and supplies more than one-third 

of its potential electric output capacity and more than 25 Mwe output to 

any utility power distribution system for sale is also considered ann 

electric utility steam generating unit.

6
Overview of Section 112

► Section 112 of CAA mandates that EPA develop standards for 

hazardous air pollutants (HAP) for both major and area sources 

listed under section 112(c).

► The section 112 definition of EGU does not distinguish between area and 

major sources.

► Major sources of HAP are those that have the potential to emit 10 tons 

per year (tpy) or more of any one HAP or 25 tpy or more of any 

combination of HAP.

► Section Section 112(d)(2) 112(d)(2) states that major that major source standards standards must be based be based 

on the maximum achievable control technology (MACT).

► Section 112(d)(3) sets minimum stringency criteria (MACT Floor) –

costs may not be considered

► For existing sources:

► “The average emission limitation achieved by the best performing 12 percent of 

existing sources..”

► For new sources, the MACT floor is:

► “The emission control achieved in practice by the best controlled similar source

7
Overview of Section 112 (cont.)

► EPA may regulate “beyond the floor” where justified – costs and 

other issues must be considered

► MACT may differ for new and existing sources.

► Section 112(d)(1) provides EPA with authority to distinguish among 

classes, types, and sizes of sources.

► Section Section 112(d)(4) 112(d)(4) provides provides EPA with discretionary EPA with discretionary authority authority to 

establish health-based emission standards for HAP for which a 

health threshold has been established.

► Section 112(h) allows the use of work practice standards instead of 

emission standards if enforcement of an emission standard is “not 

feasible”, as that term is defined in that section.

8
Utility MACT is part of a package of EPA 

Regulations Affecting the Power Sector 

► Tailoring Rule – new or modified plants much obtain permits for any increase in GHG 

emissions – final rule in May 2010

► Transport Rule (Clean Air Interstate Rule (CAIR) Remand Response) – to reduce 

SO2 and NOX emissions from existing power plants in 31 states/Washington DC –

final rule in Spring 2011

► New Source Performance Standards (NSPS) for coal- and oil-fired electric utility 

steam generating units (EGUs) – to regulate SO2, NOX, and PM emissions from new 

EGUs – final rule in November 2011

► Effluent Guidelines for steam electric power generating – to address water quality 

impacts of EGUs - final rule in January 2014

► Solid waste regulations for EGU coal ash (coal combustion residuals) –Is there a 

final deadline or expected date?

► National Emission Standards for Hazardous Air Pollutants (NESHAP) for coal- and 

oil-fired EGUs (Utility NESHAP) – to regulate hazardous air pollutant (HAP) 

emissions from new/existing EGUs – final rule in November 2011

3
Project History

► This action stems from a court decision overturning EPA’s prior 

findings and rules 

► EPA’s 2000 determination that it was “appropriate and necessary” to 

regulate emissions of hazardous air pollutants (HAP) from coal- and 

oil-fired electric utility steam generating units (EGUs) was reversed in 

March 2005, when EPA found it was neither “appropriate nor

necessary” necessary” to regulate to regulate HAP emissions HAP emissions from EGUs and removed EGUs and removed those 

units from the CAA section 112(c) source category list

► EPA substituted the Clean Air Mercury Rule (CAMR) in May 2005, 

which regulated mercury from EGUs through a cap and trade program 

under CAA section 111.

► In February 2008, the Court vacated EPA’s action that removed EGUs 

from the section 112(c) source category list and vacated CAMR.

4
Effect of Court’s Decision

► Coal- and oil-fired EGUs remain a listed source category for which 

EPA must issue emission standards under CAA section 112(d).

► EPA must address all Hazardous Air Pollutants that are emitted from 

coal- and oil-fired EGUs – not just mercury.

► EPA is operating EPA is operating under a Consent a Consent Decree negotiated negotiated with litigants with litigants

► No later than March 16, 2011, EPA shall sign a notice of proposed 

rulemaking

► No later than November 16, 2011, EPA shall sign a notice of final 

rulemaking

5
Some Legal Constraints on Section 

112 Rulemakings

► Emission standards must be established for EGUs that are located 

at major sources and at area sources.

► Voluntary or incentive-based approaches are not allowed.

► Emission standards must address all HAP emitted from EGUs.

► Standards must set technology-based limits

► Viability of health-based emission standards and work practice standards 

will be explored.

► Method for determining the minimum level of emissions control (i.e., 

MACT floor) must be followed.

► Only units in the MACT floor may be used in determining variability 

unless a demonstrated relationship between the variability of 

sources outside the floor and the variability of sources within the 

floor can be shown.

► Regulatory options more stringent than the MACT floor must be 

considered. 

9
Affected Facilities

Coal, 48%

Natural Gas, 21%

Non Hydro Renewables, 3%

Hydro, 6%

Nuclear, 20%

► Approximately 1,350 EGUs at 525 facilities Other, 1%

► Approximately 1,200 coal-fired boilers at 

approximately 450 facilities in 44 States and 

Puerto Rico

► Coal-fired EGUs include units that burn coal, 

coal refuse, or a synthetic gas derived from 

coal either exclusively, in any combination 

together, or in any combination with other 

supplemental fuels (e.g., petroleum coke, tirederived fuels).

Oil, 1%

► Bituminous coal ~ 50% of coal generation

► Subbituminous ~45% of coal generation

► Lignite ~ 5% of coal generation

► Many units are bigger sources that operate 

near their rated capacity called “base-load” 

► Base-load units are large units used to meet 

the electricity demand that is relatively 

constant.

► Approximately 48 percent of nationwide net 

generation

10
Affected Facilities (cont.)

► Approximately 150 oil-fired boilers at approximately

75 facilities, mostly in Northeast, Midwest, Florida, Hawaii, Guam, 

and Puerto Rico, 3 in Indian country

► Many units are peaking units with low capacity factor utilization over the 

past 3 – 5 years.

► Peaking units are used to meet the demand for electricity during peak 

periods of the day, and run for shorter periods of time.

► Many co-fire with natural gas or use natural gas preferentially natural gas or use natural gas preferentially but must but must 

have oil capability for use during periods of natural gas curtailments to 

industry.

► Approximately 1 percent of nationwide net generation

► Industry includes investor-owned, publicly-owned, and rural 

cooperatives.

► Natural gas was not listed in the December 2000 regulatory 

determination.

► Approximately 21 percent of nationwide net generation

11
EGU Coal Steam Units >25 MW

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Location of Coal Steam EGU units ≥ 25 MW Dataset: NEEDS4.0_Draft_03_17_09v3toEPA

12
EGU Units (Coal and Steam >25 MW) 

and Tribal Lands Overlay 
Data Needs

► Have considerable data from 1999 for mercury from coal-fired units; limited 

data for all other HAP and for oil-fired units.

► Completing a major information collection request (ICR) to obtain the 

necessary data from coal- and oil-fired units

► Data necessary for development of legally supportable regulation

► Testing Testing requirements requirements established established for a significant number for a significant number of units of units 

(some units will test more than one HAP group)

13
Rulemaking Options under 

Consideration

► Scope of rulemaking

► Pollutant-specific limits vs. use of surrogates (e.g., PM)

► Approach to assess variability

► Must explore “beyond-the-floor” options

► Subcategorization

► CAA authorizes subcategorization by class, type and size

► Will consider and evaluate bases for subcategorization

► Alternative standards available under CAA section 112

► Work Practice Standards

► Health Based Emission Limits

► Oil-fired units

► Will consider impact on marginal, low-capacity factor, peaking units for 

which compliance could result in closure

16
Pollutants Covered

► All HAP emitted from EGUs must be addressed.

► Surrogate standards are allowed if reasonable.

► Same controls will be installed regardless of use of surrogates.

► Saves on monitoring and testing costs

► Major and Area Source Portland Cement NESHAP – as amended in 2010

► Set emission limits for 5 pollutants (Hg, dioxin/furan, HCl – major sources only, 

PM, and total hydrocarbon (THC))

► Major Source Boiler NESHAP – proposed rule

► Set emission limits for 5 pollutants (Hg, dioxin/furan, HCl, PM and carbon 

monoxide (CO))

► Expect to set limits for 5 pollutants to address all HAP emitted from EGUs

► Mercury

► PM (surrogate for non-mercury HAP metals)

► SO2 or HCl (surrogate for acid gas HAP)

► CO (surrogate for non-dioxin/furan organic HAP) vs. other pollutants (e.g., 

polycyclic aromatic hydrocarbons (PAH) or formaldehyde)

► Dioxin/furan

17
Floors and Variability

► Must adhere to language of section 112 regarding MACT floors

► Determine variability based on the top performing 12 percent

► Beyond-the-floor options

► Regulatory options more stringent than the MACT floor must be considered.

► Can include additional control technologies, process changes, or other means of 

reducing HAP

► Costs and other impacts are considered.

► Major Source Boilers NESHAP Major Source Boilers NESHAP proposed one proposed one-time energy time energy audit.

18
Subcategorization

► CAA authorizes subcategorization by class, type and size

► Must be a basis for distinguishing between subcategories (e.g., design 

differences, operating mode, or other characteristics)

► EPA will consider and evaluate various bases for subcategorization

► Boiler design (e.g., units designed to burn coal vs. units designed to burn 

oil vs. IGCC)

► Coal rank (e.g., bituminous, subbituminous, lignite)

► Unit type (e.g., fluidized bed, pulverized coal)

► Oil type (e.g., residual (no. 4 and 6 oils) vs. distillate (no. 2 oil))

► Duty cycle (e.g., peaking units vs. base-load units)

► The more we subcategorize, the more data needed to establish the 

MACT floor

19
Alternative Standards Available 

under CAA section 112(d)(4)

► EPA has discretionary authority to establish health-based emission 

standards for HAP for which a health threshold has been 

established.

► Provision is intended for cases where a less stringent emission standard 

will still ensure that the health threshold will not be exceeded, with an 

ample margin of safety.

► Solicited comment on a number of specific issues associated with regulation 

under section 112(d)(4)

21
Alternative Standards Available 

under CAA section 112(h)

► Work practice standards are allowed instead of emission standards 

if it is not feasible to prescribe or enforce an emission standard.

► “Not feasible to prescribe or enforce an emission standard” is defined, in 

part, to mean that “the application of measurement methodology to a 

particular class of sources is not practicable due to technological and 

economic limitations” (emphasis added).

23
Control Technologies Potentially 

Required to Meet Standards

► Mercury and PM (surrogate for non-mercury metal HAP)

► A new fabric filter installation is likely to be capable of achieving the PM emission 

limits and will likely assist in achieving the mercury emission limits

► If a unit already equipped with a fabric filter emits Hg above the emission limit, the 

incremental Hg removal required to meet the limit can likely be achieved with 

installation of activated carbon injection (ACI) technology

► SO2 or HCl (surrogate for acid gas HAP)

► Either a wet scrubber or dry sorbent injection system is likely to be capable of 

achieving the SO2 or HCl emission limit

► If a unit already equipped with a wet scrubber or dry sorbent injection system 

emits SO2 or HCl above the emission limit, the incremental required SO2 or HCl 

removal can likely be achieved by increasing the sorbent injection rate into the 

scrubber or the flue gas

► CO (surrogate for non-dioxin/furan organic HAP)

► Organic HAP and CO are likely to be controlled to required levels by improving the 

combustion efficiency of the unit

26
Questions?

Project Lead: Bill Maxwell

919-541-5430

maxwell.bill@epa.gov

SBREFA Contacts: Mary Johnson

919-541-5025

johnson.mary@epa.gov

Project Oversight: Bob Wayland

919-541-1045

wayland.robertj@epa.gov

31

Madeline Barch

202-564-0234

barch.madeline@epa.gov
Appendix
Project Background

► On 12/20/2000, pursuant to section 112(n)(1)(A), EPA determined that 

it was “appropriate and necessary” to regulate emissions of hazardous 

air pollutants (HAP) from coal- and oil-fired EGUs under CAA section 

112.

► Based on that determination, EPA listed EGUs for regulation pursuant to 

CAA section 112(c).

► On 03/29/2005, EPA issued the Section 112(n) Revision Rule that 

found it was neither “appropriate nor necessary” to regulate HAP 

On 03/29/2005, EPA issued the Section 112(n) Revision Rule that 

found it was neither “appropriate nor necessary” to regulate HAP 

emissions from EGUs and removed such units from the section 112(c) 

source category list.

► The reversal of the 2000 “appropriate and necessary” finding was based, in 

large part, on projected mercury reductions achieved as a co-benefit of 

CAIR.

► On 05/18/2005, EPA issued the Clean Air Mercury Rule (CAMR), 

which regulated mercury from EGUs through a cap and trade program 

under section 111.

A-1
Recent Legal History

► 02/08/2008 – D.C. Circuit Court of Appeals vacated the Section 

112(n) Revision Rule and CAMR

► 03/14/2008 – Mandate Issued in Section 112(n) Revision Rule and 

CAMR vacaturs

► 10/17/2008 – U.S. Government filed a petition for writ of certiorari 

with the U.S. Supreme Court

► 12/18/2008 12/18/2008 – Mandatory Mandatory duty suit filed by duty suit filed by American Nurses American Nurses Assn., 

et al., for failure to establish MACT standards for coal- and oil-fired 

electric generating units by 12/20/2002

► 02/06/2009 – U.S. Government moves to withdraw its petition for 

writ of certiorari 

► 02/23/2009 – U.S. Supreme Court denies industry petition for writ 

of certiorari and grants U.S. Government’s request to withdraw its 

petition

A-2
Effect of Vacatur

► Coal- and oil-fired EGUs remain a listed source category for which 

EPA must issue emission standards under CAA section 112(d).

► EPA will address all HAP that are emitted from coal- and oil-fired 

EGUs – not just mercury.

► Operating under a Consent Decree negotiated with litigants 

(American Nurses Assn., et al.; represented by Earthjustice)

► No later than March 16, 2011, EPA shall sign for publication in the 

Federal Register a notice of proposed rulemaking

► No later than November 16, 2011, EPA shall sign for publication in the 

Federal Register a notice of final rulemaking

A-3
Project History

► In December 2000, EPA determined that it was “appropriate and 

necessary” to regulate emissions of hazardous air pollutants (HAP) 

from coal- and oil-fired electric utility steam generating units (EGUs) 

and added such units to the CAA section 112(c) list of sources to be 

regulated under CAA section 112.

► In March 2005, EPA found it was neither “appropriate nor necessary” 

to regulate regulate HAP emissions HAP emissions from EGUs from EGUs and removed and removed those units from units from 

the CAA section 112(c) source category list.

► In May 2005, EPA issued the Clean Air Mercury Rule (CAMR), which 

regulated mercury from EGUs through a cap and trade program under 

CAA section 111.

► In February 2008, the Court vacated EPA’s action that removed EGUs 

from the section 112(c) source category list and vacated CAMR.

4
Data Needs

► Have considerable data from 1999 for mercury from coal-fired units; limited 

data for all other HAP and for oil-fired units.

► Completing a major information collection request (ICR) to obtain the 

necessary data from coal- and oil-fired units

► 1,332 units to provide updated facility information on boiler, fuels, controls, etc. 

and all available data from past 5 years

► Requires emission testing of ~800 units

► Approximately 95% of data collection is complete; analyses are ongoing

► “Air Toxics Standards for Utilities” web page can be found at: 

http://www.epa.gov/ttn/atw/utility/utilitypg.html

► Data files of emissions data (Microsoft Access format)

► Extracted data worksheets (Microsoft Excel format) 

► Data necessary for development of legally supportable regulation

► Need sufficient representative data for MACT floor determinations

► Need data on variability 

► Need data on range of fuels

► Need data to demonstrate that any surrogate standards are reasonable

13
Utility MACT Information Collection

► Testing requirements (some units will test more than one HAP group)

► 170 coal-fired units for acid gas HAP

► e.g., hydrogen chloride (HCl), hydrogen fluoride (HF), hydrogen cyanide (HCN)

► Selected as being among the top performing units

► 170 coal-fired units for non-dioxin/furan organic HAP

► Selected as being among the top performing units

► 170 coal-fired units for metallic HAP

► e.g., mercury, cadmium, chromium, lead

► Selected as being among the top performing units

► 50 coal-fired units for dioxin/furan organic HAP

► Selected at random from the entire coal-fired EGU population

► 50 coal-fired units for acid gas, non-dioxin/furan organic, and metallic HAP

► Selected at random from the population of “non-top performing units”

► 2 coal-fired integrated gasification combined cycle (IGCC) units for all HAP 

(i.e., acid gas, organic, metallic)

► 100 oil-fired units for all HAP

► Selected at random from the oil-fired EGU population

► 16 petroleum coke-fired units for all HAP

14
Floors and Variability

► Must adhere to language of section 112 regarding MACT floors

► Determine variability based on the top performing 12 percent

► May not go outside the top performing 12 percent unless EPA can show a 

demonstrated relationship between the variability of the worst performers and the 

variability of the best performers.

► May include fuel variability and performance variability

► Will look at load variability

► Recent regulatory actions (Portland Cement NESHAP and Major Source Boilers 

NESHAP) have assessed variability based on the 99th percentile upper predictive 

limit (UPL).

► Means that for a future test from a best performing source, there is 99 percent 

confidence that the reported level will fall at or below the UPL value

► Beyond-the-floor options

► Regulatory options more stringent than the MACT floor must be considered.

► Can include additional control technologies, process changes, or other means of 

reducing HAP

► Costs and other impacts are considered.

► Major Source Boilers NESHAP proposed one-time energy audit.

18
Subcategorization

► The more we subcategorize, the more data needed to establish the MACT floor – 5 

data points for each subcategory with less than 30 sources and sufficient data to take 

top 12% of available data for subcategories with 30 or more sources. 

► Portland Cement NESHAP – final rule

► No subcategories

► Discussion begins in last paragraph of page 54977 of 75 FR 54970, September 9, 

2010

► http://frwebgate2.access.gpo.gov/cgi-bin/PDFgate.cgi?WAISdocID=8SWVqI/0/2/0&WAISaction=retrieve 

► Major Source Boilers NESHAP – proposed rule

► Proposed rule included 11 subcategories based on boiler “type”

► 3 coal subcategories (pulverized coal, stokers, fluidized bed units)

► 4 biomass subcategories (stokers, fluidized bed units, suspension 

burners/dutch ovens, fuel cells)

► 1 liquid subcategory

► 2 gas subcategories (natural gas/refinery gas, other gases)

► 1 metal processing furnace subcategory

► Discussion begins in last paragraph of page 32016 of 75 FR 32006,

► June 4, 2010

► http://frwebgate1.access.gpo.gov/cgi-bin/PDFgate.cgi?WAISdocID=e61yXI/0/2/0&WAISaction=retrieve

20