Mercury and Air Toxics Standards:

Overview of Final Rule

Briefing for OMB

November 15, 2011
Overview

► Comments on Proposal

► NESHAP: Key Issues and Final Decisions

► Impacts of Final MATS 

► NSPS for Criteria Pollutants: Key Issues and Final 

Decisions

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Overview of Comments

► More than 900,000 comments received on proposal

► Over 700,000 on NESHAP and over 207,000 on NSPS

► More than 22,000 unique comments 

► Hundreds of significant comments on NESHAP, including 10,000 

pages of comments and attachments

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Key Comments from Stakeholders –

Environmental Community and Tribes

► Environmental community had rule and structure 

comments

► Limits should be more stringent

► Coal should not be subcategorized

► Reliability of grid not impacted and compliance can be achieved in 

3 years

► Tribal comments were mixed

► Most Tribes support changes such as more stringent limits and 

less subcategorization

► Some Tribes are against the regulation as it pertains to their 

specific situation

► The impact of MATS on Tribal water rights in the Southwest (e.g., 

Navajo Generating Station) is a particular issue

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Key Comments from Stakeholders – States

► State support is mixed

► Northeastern states more supportive

► Believe limits should be more stringent – CT, NJ, NY

► Outside Northeast, less supportive

► Proposed limits appear unachievable and should not regulate PM 

under section 112 – NM

► Against pollutant-by-pollutant approach – NM

► Withdraw Withdraw rule and better coordinate ule and better coordinate costs of all agency costs of all agency actions actions – AZ, 

FL, IA, IN, KS, KY, OH, OK, UT, VA, WY

► Rule is unlawful – NE

► Many concerned about compliance time, implementation burden, 

and impact on States’ economies

► Testing requirements burdensome – CT, PA, SC

► November 16 deadline should be extended – NM, FL, VA

► Delegate to states and provide flexibility – CO, OK, PA, SC, WI

► Extend compliance period – AL, AR, DE, FL, IN, MI, VA, WI, WV

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Key Comments from Stakeholders – Electric 

Utility Industry

► Electric utility industry not united in their position on MATS

► Some support and some do not

► However, absence of comment on an issue should not be misinterpreted

► Industry appears to have partitioned out pieces of their comments

► Majority of coal-fired electric utility industry not supportive

► Limits should be less stringent

► Subcategories should be added

► Compliance time should be extended to avert grid reliability issues

► Filterable particulate matter (PM) should be used rather than total PM

► Limited-use subcategories for coal and oil should be added

► Minority of EGU industry (e.g., Clean Energy Group (CEG), Exelon)

generally supportive of MATS

► 3-year compliance time generally appropriate

► Proposed subcategories appropriate

► Some of EGU industry agrees with majority on some issues but minority on 

others – no uniform consistency

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Key Comments from Stakeholders – Unions 

and General Industry

► Unions for Jobs and the Environment (UJAE) (consortium of unions, including 

boilermakers, teamsters, mine workers)

► Extend compliance time

► Delay promulgation date

► Jobs impacts incorrect

► Retirement projections low

► Basis for new-source MACT

► Against pollutant-by-pollutant approach

► Council of Industrial Boiler Owners (CIBO)

► MATS will adversely affect the cost-effective operation of industrial energy operations 

► Multiplicity of agency rules will drive up compliance costs and impact ability to comply with the 

deadlines

► Filterable PM should be the surrogate

► U.S. Chamber of Commerce

► MATS does not comply with Executive Order 13563, Executive Order 12866, the Regulatory 

Flexibility Act, the Unfunded Mandates Reform Act, or the Information Quality Act

► Institute of Clean Air Companies (ICAC)

► Existing-source limits achievable

► New-source limits questionable

► Concerns about continuous emission monitoring system (CEMS) requirements for new 

sources

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NESHAP: Key Issues

► Many issues resolved without significant change to proposed rule

► Some proposed emission limits adjusted

► Adjustments to monitoring provisions for clarity and consistency

► Comments received suggesting changes – some on issues for which we

solicited comment and others based on logical outgrowth

► Coal-Fired Units

► New-source limit

► Subcategorization

► Compliance schedule

► Surrogate for non-mercury metal HAP

► Oil-Fired Units

► Surrogate for acid gas HAP

► Surrogate for total HAP metals

► Subcategorization of distillate and residual oil

► General

► Monitoring

► Area sources

► Startup/shutdown

► Limited-use subcategory

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NESHAP: New Coal-Fired Sources

► Comments received

► Some industry and union stakeholders expressed concern that 

there were no sources that could meet all of the required 

standards simultaneously

► Believe that new source limits should be based on sources that model what a 

new source would look like to comply with MATS, NSPS, and other air 

regulations

► Opposed to pollutant-by-pollutant approach

► Argue that pollutant controls can increase pollutants – most concern 

with PM because injecting sorbents to reduce other pollutants 

increases PM

► No significant comments from other stakeholders

► Final rule: Revised standards that can be met by an 

existing source

► Used same general approach as proposal but reassessed data

► Logan Generating Station Unit 1, located in NJ, meets all three 

new-source emission limits and has full suite of controls

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NESHAP: Subcategorization of Coal-Fired Units

► Comments received

► Environmental community against any subcategorization beyond 

coal/oil 

► Promotes use of “junk” coal and is illegal

► Most of industry supports additional subcategorization (e.g., <100 

MWe, fluidized bed combustion (FBC)) beyond what proposed

► Commented that our premise for the proposed “coal <8,300 Btu/lb with 

a height/depth ratio >3.82” subcategory is not supported

– Limits should be higher and height/depth ratio does not work for FBC units

► Final rule: Keep same general subcategories as in 

proposal

► Revise definition to be use of low Btu, virgin coal rather than 

relying on other design characteristics (e.g., height to depth 

ratio)

– Makes clear that FBC units that fire low Btu, virgin coal are included

► No other subcategories supported by data

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NESHAP: Compliance Schedule

► Comments received

► Environmental community and some industry commenters believe 3 

years is sufficient

► Most industry commenters believe that additional years are necessary to 

address reliability issues and reasonable permitting/construction time

► Final rule: Expanded discussion of what qualifies for 1 

year compliance extension and discussion of compliance 

options beyond 4 years

► Explained permitting authorities should consider larger group of 

activities for compliance extension: emission controls, on-site 

generation and in cases that impact reliability: off-site generation, 

transmission upgrades, units needed to cover for units off-line to install 

controls 

► Constrained by statute to 3-year compliance + 1 year potential additional 

by permitting authority

► Explain that EPA is developing enforcement guidance to address reliability 

related issues beyond 4 years

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NESHAP: Surrogate for

Non-mercury Metal HAP for Coal-Fired Units

► Comments received

► Environmental community opposes surrogates

► Industry commenters support surrogates but believe filterable PM 

should be used instead of total PM as the surrogate for nonmercury metallic HAP

► Note that the primary non-mercury metallic HAP in condensable PM is 

selenium; selenium can be addressed through acid gas standards

► Final rule: Establish filterable PM as surrogate for nonmercury metallic HAP and require PM CPMS (not 

CEMS); condensable HAP would be addressed by acidgas HAP limits

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NESHAP: Surrogate for

Acid Gas HAP for Oil-Fired Units

► Comments received

► Most industry commenters want oil moisture content used as the 

surrogate for HCl/HF rather than testing for each

► Provided limited information suggesting chloride/fluoride in oil results 

from sea-water ballast contamination from single-hull tankers

► No flue gas desulfurization (FGD) systems on oil-fired units so HCl/HF 

control unclear

► Environmental Environmental community did not comment community did not comment on oil-fired issues fired issues 

specifically

► Final rule: Establish 1.0% oil moisture content as 

alternate compliance option, with HCl/HF limits as 

alternatives

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NESHAP: Surrogate for 

Non-Mercury Metal HAP for Oil-Fired Units

► Comments received

► Most industry commenters want PM to serve as a surrogate for 

total HAP metals rather than testing for either total metals or 

individual metals

► Believe that there is a correlation

► No comments from environmental community on oil-fired issues 

specifically

► Final rule: Establish filterable PM as a surrogate for total 

HAP metals with total HAP metal limits as alternative

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NESHAP: Subcategorization of 

Oil-Fired Units

► Comments received

► Most industry commenters recommend subcategories of 

distillate/residual oil and non-continental/continental sources

► Final rule: Establish continental/non-continental 

subcategory and maintain common distillate/residual 

category

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NESHAP: Limited-use Subcategory

► Comments received

► Most industry stakeholders favor limited-use subcategory for both 

coal and oil

► Situations, such as periods of natural gas curtailment or periods of 

high demand, when oil must be used to maintain grid load or stability

► Final rule: Limited-use subcategory for oil-fired EGUs 

<5% capacity factor on oil with work practice standard of 

annual tune-up

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NESHAP: Area Sources

► Comments received

► Industry favors area source designation

► Claim that EPA is legally bound to establish GACT limits for area 

sources

► Claim that small entities (e.g., cities) would be aided by area source 

determination

► Environmental community opposed

► Numerous large EGUs (i.e., hundreds of MW) claim to be area 

sources

► Final rule: No change from proposal (i.e., no area source 

designation)

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NESHAP: Startup/Shutdown

► Comments received

► Many industry stakeholders commented that EPA failed to 

propose work practice standards during periods of 

startup/shutdown as was done in Industrial Boiler NESHAP

► Environmental stakeholders point to Texas permits that contain 

limits for startup/shutdown periods and other data that indicate 

high emissions during these periods

► Final rule: Establish work practice standards in final rule; 

commit to reviewing data to see if changes would be 

warranted in future 8-year review

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5.8

3.3

1.9

0

1

2

3

4

5

6

7

Millio

n

T

o

ns

2015 SO2 from Coal > 25 MW

Base MATS

53

27

8

0

10

20

30

40

50

60

T

o

ns

2015 Hg from Coal > 25 MW

Base MATS

Emissions from Covered Sources

0

2009 MATS RIA

0

2005 MATS RIA

351.6

45.3

5.5

0

50

100

150

200

250

300

350

400

2005 MATS RIA

T

h

o

usan

d

T

o

ns

2015 HCl from Coal > 25 MW

Base MATS

Note: Historic HCl emissions based on single emission factor; projected 

emissions based on fuel-specific Cl assumptions and removal efficiencies.

► The base case includes the final Cross-State Air 

Pollution Rule and other existing Federal and state 

controls and enforceable agreements.†

► Emission totals presented here reflect all covered coal 

steam and IGCC electric generating units > 25 MW.

► The policy case models the effect of the MATS mercury 

and HCl emission rates on these units, and it applies 

ESP upgrades or fabric filter retrofits to units to reflect 

the MATS PM standard.

† EPA’s MATS baseline excludes non-federal mercury regulation to remain 

consistent with the rule’s risk assessment modeling approach.

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180

29

9 7

91

0

174

51 53

146 140

197

52

50

100

150

200

250

T

o

t

al C

a

p

a

cit

y (G

W)

Base MATS RIA

Pollution Controls on Coal-Fired Capacity

9 7 0

0

Wet FGD Dry FGD DSI SCR ACI FF ESP Upgrade

► FGD = Flue Gas Desulfurization (92 - 96% SO2removal and 99% HCl removal)

► SCR = Selective Catalytic Reduction (90% NOxremoval)

► DSI = Dry Sorbent Injection (70% SO2removal and 90% HCl removal)

► DSI is able to meet the analyzed HCl emissions standard with use of multiple coal types less than 2 

lb/MMBtu SO2

► ACI = Activated Carbon Injection (90% mercury removal)

► FF = Fabric Filter, also called a baghouse (PM control)

► ESP = Electrostatic Precipitator (PM control)

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10.9

9.2

0

2

4

6

8

10

12

Billio

n

$

2

0

0

7

2015 Incremental Compliance Costs

for the Power Sector

-0.2

9.9

-0.5 -0.8 -0.1

5.5

0.1

-0.4 0

2

4

6

8

10

12

CC Coal Steam CT Nuclear

C

a

p

acity (G

W)

Incremental Retired Capacity in 2015 

Proposed

MATS RIA

2015 Capacity

(post-retirements)

Total: 1,020 GW

Coal Steam: 304 GW

Evolution of Results from Proposal to Final

0

Proposed MATS RIA

CC Coal Steam CT Nuclear

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 Key changes from modeling of the proposal include:

 Not all chlorine in subbituminous and lignite coal is emitted as HCl. The alkalinity of ash from 

those coals reacts with the acid gas to capture a portion of its emissions even without control 

equipment. Post-proposal modeling assumes 75% HCl capture from subbituminous and 

lignite coal ash, based on analysis of data reported under the 2010 ICR.

 Whereas at proposal a fabric filter was assumed necessary for PM control, this updated 

modeling includes ESP upgrades as a more cost-effective alternative for certain EGUs
Sensitivity to Limit DSI Installations by 2015

 EPA has modeled a MATS sensitivity scenario limiting 

DSI retrofitting to 35 GW

 Addresses concerns that DSI may not be as widely applicable as 

represented in core policy modeling

 Annual compliance costs rise by about $1.2 billion, reaching 

$10.3 billion in 2015

 About 1 GW of additional capacity withdraws from service

 SO2 emissions are reduced by a further 55,000 tons, as many 

units previously projected to install DSI switch to dry FGD instead

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NSPS for Criteria Pollutants: 

Overall Recommendation

► Key comments

► Environmental community

► More stringent standards based on projected IGCC emission rates

► Establish separate condensable and filterable PM standards 

– Criteria pollutant proposal included a combined standard (based on EGU NESHAP 

standard)

► Electric utility industry groups

► Standards are unachievable and should be less stringent

► Insufficient data to establish a condensable PM standard or identify the best 

demonstrated technology

► Best demonstrated technology for control of SO2 not clearly identified 

► Industry and Environmental groups: how will the GHG NSPS impact the 

criteria NSPS?

► CCS is expected to increase some criteria pollutant emission rates and 

decrease others

► Final rule:

► Finalize NOX and SO2 standards as proposed 

► Finalize filterable PM standard to be consistent with EGU NESHAP 

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Benefits and Costs of the Penultimate MATS 

IPM Run (Billions of 2007$)

3% Discount Rate 7% Discount Rate

Total Monetized Benefits $37 to $91 $33 to $82

Hg-related benefits $0.004 to $0.006 $0.0005 to $0.001

PM2.5-related co-benefits $37 to $90 $33 to $81

Climate-related co-benefits $0.35 $0.35

Total Costs $9.2 $9.2

Net Benefits $28 to $81 $24 to $72

Non-monetized Benefits

Visibility in Class I areas

Other neurological effects of Hg exposure

Health effects from exposure to non-Hg HAP

Health effects of ozone and direct exposure to SO2 and NO2

Ecosystem effects

Health effects from commercial and non-freshwater fish consumption

Health risks from exposure to non-mercury HAP

Notes:

• All estimates are for 2016 and are rounded to two significant figures.

• Climate-related co-benefits are calculated using the Social Cost of Carbon at a 3% discount rate.

• Mercury benefits were calculated using the baseline from proposal. The difference in emission reductions between 

proposal and final would not substantially affect mercury benefits.

• Total social costs are approximated by compliance costs. This total does not include monitoring or reporting costs.

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Appendix

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Coal-fired Units: Draft Final Existing

Source NESHAP Limits

Subcategory

Filterable 

particulate 

matter (PM)

Hydrogen 

chloride (HCl)

Mercury

(Hg)

SO2

(alternate)

Total HAP 

metals 

(alternate)***

Existing non-low 

Btu, virgin coal

EGU

0.030 lb/MMBtu

(0.030 lb/MMBtu)*

0.0020 lb/MMBtu

(0.0020 lb/MMBtu)

1.2 lb/TBtu

(1.2 lb/TBtu)

0.20 lb/MMBtu

(0.20 lb/MMBtu)

0.000050 

lb/MMBtu

(0.000040 

lb/MMBtu)

Existing low Btu, 

virgin coal EGU

0.030 lb/MMBtu

(0.030 lb/MMBtu)*

0.0020 lb/MMBtu

(0.0020 lb/MMBtu)

3.3 lb/TBtu**

(4.0 lb/TBtu)**

0.20 lb/MMBtu

(0.20 lb/TBtu)

0.000050 

lb/MMBtu

(0.000040 

lb/MMBtu)

Existing – IGCC 0.040 lb/MMBtu

(0.050 lb/MMBtu)*

0.00050 lb/MMBtu

(0.00050 lb/MMBtu)

2.2 lb/TBtu

(3.0 lb/TBtu) NA

0.000050 

lb/MMBtu

(0.000050 

lb/MMBtu)

* Total PM

** Beyond-the-floor limit that is being finalized.

*** Individual HAP metal limits are also being finalized as alternate limitations

Numbers in (blue) are the proposed limits

Draft final limits do not yet account for rounding

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Coal-fired Units: Draft Final New

Source NESHAP Limits

Subcategory

Filterable 

particulate 

matter (PM)

Hydrogen 

chloride (HCl)

Mercury

(Hg)

SO2

(alternate)

Total HAP 

metals 

(alternate)**

New non-low Btu, 

virgin coal EGU

0.0050 lb/MWh

(NA)

0.40 lb/GWh

(0.30 lb/GWh)

0.00020 lb/GWh

(0.00020 lb/GWh)

0.40 lb/MWh

(0.40 lb/MWh)

0.060 lb/GWh

(0.040 lb/GWh)

New low Btu, New low Btu, 0.0050 lb/MWh 0.40 lb/GWh 0.040 lb/GWh 0.40 lb/MWh 0.060 lb/GWh

virgin coal EGU

0.0050 lb/MWh

(NA)

0.40 lb/GWh

(0.30 lb/GWh)

0.040 lb/GWh

(0.040 lb/GWh)

0.40 lb/MWh

(0.40 lb/MWh)

0.060 lb/GWh

(0.040 lb/GWh)

New – IGCC 

0.070 lb/MWh 

0.090 lb/MWh** ***

(NA)

0.0030 lb/MWh

(0.30 lb/GWh)

0.0030 lb/GWh***

(0.000010 lb/GWh)

0.40 lb/MWh

(NA)

0.30 lb/GWh

(0.040 lb/GWh)

* Beyond-the-floor limit that is being finalized

** Individual HAP metal limits are also being finalized as alternate limitations

*** Based on permit limits received in public comments

  Duct burners on syngas

** *** Duct burners on natural gas

Numbers in (blue) are the proposed limits

Draft final limits do not yet account for rounding

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Oil-fired Units: Draft Final New and Existing 

Source NESHAP Limits

Subcategory Filterable PM*

Hydrogen chloride 

(HCl)**

Hydrogen fluoride 

(HF)**

Mercury

(Hg)

Existing – Liquid oil –

continental

0.030 lb/MMBtu

(NA)

0.0020 lb/MMBtu

(0.00030 lb/MMBtu)

0.00040 lb/MMBtu

(0.00020 lb/MMBtu) NA

Existing – Liquid oil –

non-continental

0.030 lb/MMBtu

(NA)

0.00020 lb/MMBtu

(NA)

0.000060 lb/MMBtu

(NA) NA

New – Liquid oil –

continental

0.070 lb/MWh

(NA)

0.00020 lb/MWh

(0.00050 lb/MWh)

0.00020 lb/MWh

(0.00050 lb/MWh) NA

New – Liquid oil –

non-continental

0.20 lb/MWh

(NA)

0.0020 lb/MWh

(NA)

0.00050 lb/MWh

(NA) NAnon-continental (NA) (NA) (NA)

Subcategory Filterable PM Hydrogen 

chloride (HCl)

Mercury

(Hg)

SO2

(alternate)

Total HAP 

metals 

(alternate)*

Existing – Solid 

oil-derived 

0.0080 lb/MMBtu

(NA)

0.0050 lb/MMBtu

(0.0050 lb/MMBtu)

0.20 lb/TBtu 

(0.20 lb/TBtu)

0.30 lb/MMBtu

(0.40 lb/MMBtu)

0.000040 

lb/MMBtu

(0.000050 

lb/MMBtu)

New – Solid oilderived0.020 lb/MWh

(NA)

0.00030 lb/MWh

(0.00030 lb/MWh)

0.0020 lb/GWh

(0.0020 lb/GWh)

0.40 lb/MWh

(0.40 lb/MWh)

0.60 lb/GWh

(0.20 lb/GWh)

* Individual and total HAP metal limits are also being finalized as alternate limitations; includes Hg

** Alternate to percent moisture limitation in the oil

Numbers in (blue) are the proposed limits

Draft final limits do not yet account for rounding

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