Proposed Rulemaking for 

Industrial, Commercial, and Institutional 

Boilers at Area Sources

E.O. 13132 “Federalism” Consultation Meeting

Robert J. Wayland, Ph.D.

Leader, Energy Strategies Group

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

March 24, 2010

Draft Deliberative Document –

Do Not Quote or Cite
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RULEMAKING

 National Emission Standard for Hazardous Air 

Pollutants (NESHAP) for Area Sources: Industrial, 

Commercial, and Institutional Boilers

 Being proposed as required by section 112 of the Clean Air 

Act

 Schedule

 Proposal – April 15, 2010 (Court-ordered)

 Will be a 45 day public comment period

 Promulgation – December 16, 2010 (Court-ordered)
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Overview of Section 112

 Section 112 of CAA mandates that EPA develop standards for 

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

 Major source is a facility that emits or has PTE 10 tpy of single HAP or 

25 tpy of total HAP

 Area source is a facility that is not a major source

 Section 112(d)(2) states that standards are based on the maximum 

achievable control technology (MACT)

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

 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...”
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Overview of Section 112

 Section 112 requires EPA to publish a list of area sources that emit 

HAP

 Listings

 112(k) area source category list

 Industrial boilers

 Institutional/commercial boilers

 112(c)(6) list of source categories accounting for 90% of emissions of 7 

listed HAP

 Industrial boilers

 Institutional/commercial boilers

 Section 112 (d)(1) allows EPA to subcategories based on class, type, 

or size of sources in establishing standards.

 Section 112(h) allows EPA to promulgate a work practice standard, 

in lieu of a numerical emission limit, if it is not feasible to enforce an 

emission standard

 Not feasible means the application of measurement methodology is not 

practicable due to technological and economic limitations 
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Statutory Provisions for Area Sources

 Section 112(d)(5) allows for area source standards based on 

GACT (Generally Available Control Technology)

 Major source standards are based on MACT

 Under GACT may consider costs and economic impacts

 Focus of standards is on the 30 Urban HAP

 EPA may exempt area sources from Title V if we determine 

compliance would be impracticable, infeasible, or unnecessarily 

burdensome

 Section 112(c)(6) requires listed categories be subject to MACT 

 Both industrial boilers and institutional/commercial boilers are on 

list of 112(c)(6) source categories (for coal, wood, and oil 

combustion)

 Mercury

 Polycyclic organic matter (POM)
Background - What Sources Will The Boiler Area 

Source Rule Cover?

 Will cover an estimated 183,000 boilers at area sources at an estimated 

92,000 facilities

 The area source category only includes boilers combusting coal, biomass, or oil

 Industrial boilers - 14% 

 Commercial boilers – 19%

 Institutional boilers – 67%

 There are an estimated 1.3 million gas-fired boilers located at area sources that are not 

included in the source category

 Includes boilers used in

 commercial establishments

 stores/malls, laundries, apartments, restaurants, hotels/motels,

 Institutions

 medical centers (hospitals, clinics, nursing homes)

 educational (schools, universities)

 municipal buildings (courthouses, prisons) 

 The area source boilers have generally not been subjected to 

regulation/permitting, so little is known about them.

 About 85% of area sources are estimated to be small entities

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Boiler Area Source Rule - Proposed Subcategories

 Three subcategories based on design type:

 Coal-fired units

 3,700 units

 Biomass-fired units

 11,000 units

 Liquid fuel-fired units

 168,000 units
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Boiler Area Source

Options Currently Being Considered

 Mercury & POM

 MACT emission limits – required under 112(c)(6)

 Carbon monoxide (CO) limit as surrogate for POM

 Likely control technology basis

 Hg: fabric filter/fuel switching

 POM: GCP (annual tune-up)/burner replacement

 Work practice standard – if can be justified under section 112(h), that is, it is impracticable to enforce 

the standards to both technical and economic limitations

 Good combustion controls

 Annual tune-up

 Energy audits

 Reduced fuel use = reduced emissions of Hg and POM

 Other HAP (metals, organic HAP)

 GACT emission limits

 PM as surrogate for metals

 CO as surrogate for organic HAP

 GACT management practice standard

 Improved efficiency = Reduced fuel use = reduced emissions

 Good combustion controls

 Annual tune-up

 Energy audits

 Installation of energy efficient boiler (New boilers)

 Exempting area sources from Title V permitting

 If we can determine compliance would be impracticable, infeasible, or unnecessarily 

burdensome

 Others?
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Option Under Consideration for Proposal

 Existing units

 Limits for the three subcategories for:

 PM (as surrogate for urban metals) – based on GACT

 Mercury – based on MACT

 CO (as surrogate for POM and other urban organic HAP) – based on MACT

 Technology basis - baghouse (metals/Hg)/good combustion practices 

(organic HAP)

 Emissions limits would only be applicable to units with heat input 

capacities 10 million Btu/hour or greater

 Work practice standard (annual tune-up) being considered under section 

112(h) for units with heat input capacities less than 10 million Btu/hour

 Work practice standard (energy assessment) being considered for all area 

source facilities as a beyond-the-floor standard.

 Only applicable to area source facilities have a boiler larger than 10 million 

Btu/hour.
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Option under Consideration for Proposal

 New units

 Considering limits for each of the three subcategories for:

 PM (as surrogate for urban metals)

 Mercury

 CO (as surrogate for POM and other urban organic HAP)

 Technology basis - baghouse (metals/Hg)/carbon injection (Hg)/good 

combustion practices (organic HAP)

 Emissions limits would be applicable to all units, regardless of size

 No work practice standards being considered

 No beyond-the-floor standard being considered
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Testing and Monitoring Requirements Being Considered

 Testing:

 Initial compliance tests (PM, mercury, and CO)

 Annual performance tests

 Annual tune-up for boilers less than 10 million Btu/hour in size

 Monitoring

 Process parameters (opacity, pressure drop, sorbent injection rate, fuel, 

etc.) 

 CO CEMS for units with heat input capacity of 100 million Btu/hour or greater

 Continuous Compliance

 Demonstrated by maintaining operating limits (process parameters)
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Potential Impacts

 Cost Impacts

 Total capital investment (TCI) for existing boilers = $15.6 billion

 Existing units = 182,666

 Total annualized cost (TAC) for existing boilers = $5.5 billion

 Testing/monitoring TAC = $530 million

 Energy Assessment (Audit) = $145 million

 Breakdown of state and local by government facilities

* Note: Many of these facilities may not be state or local facilities. 

SIC No. Sector No. of Existing Facilities TAC

Total Small Large

80 Health 

Services

17,206* 15,293 1913 $1.05 billion

82 Educational 

Services

34,052* 33,303 749 $402 million

91-98 GovernmentOwned

Buildings

5,796* 5,098 698 $509 million

Total = 57,054* 3,360* $2.2 billion
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Flexibilities

 Note: CAA mandates a minimum stringency (i.e., MACT Floor) which 

can’t be reduced based on cost or economic. 

 Boiler Area Source

 Based standards on GACT (Generally Available Control Technology)

 MACT required for Hg and POM

 Promulgate a work practice standard instead of emission limits

 if it is not feasible to enforce an emission standard

 Stack testing and monitoring not required

 Exempt area sources from Title V if compliance is determine to be 

impracticable, infeasible, or unnecessarily burdensome