Summary of Major Changes From March 2011 Boiler Final Rules

Boiler MACT (Major Source)

1. Dioxin work practices

a. Work practice standards, in lieu of numeric emission limits, for dioxin/furan 

emissions for all subcategories

2. PM now considered a combustion-based pollutant for biomass

a. Separate PM emission limits for each design-based biomass subcategory instead 

of single limit for all units firing biomassl

3. Total selected metals

a. Alternate TSM emission limits (to PM emission limits) for subcategories

4. CO CEMS

a. Alternate CO CEMS-based emission limits (to stack test –based limits) for 

subcategories with CEMS data, couple with CEMS-based monitoring

5. Emission limit changes, based on the following:

a. New data

b. Changes to old data based on data QA efforts

c. Shifting of units between subcategories

d. 99% UPL for CO instead of 99.9%

e. Changes to existing source emission limits:

i. 13 limits are more stringent, 20 are less stringent, and 2 are the same

f. Changes to new source emission limits:

i. 7 limits are more stringent, 24 are less stringent, and 4 are the same

6. Subcategory changes

a. Separate subcategories for units designed to combust light or heavy liquids

instead of single liquid fuel subcategory

b. Separate subcategories for kiln-dried biomass stokers and wet biomass stokers

instead of a single biomass stoker subcategory

c. A new coal fluidized bed with fluidized bed heat exchanger subcategory

7. Monitoring changes

a. Proposing the use of O2 trim systems instead of O2 CEMS

b. 30-day rolling averages for most parameter monitoring instead of 12-hour bloch 

averages

c. PM CEMS requirement removed for biomass units

d. PM CEM requirement for other large units changed to a parameter monitoring 

system.

8. Control Costs (2008$)

a. March 2011 rule: $1.4 billion per year 

b. Reconsideration final: $1.4 billion per year

9. Benefits (2008$)

a. March 2011 rule: $20 billion to $49 billion per year (7% discount rate)

b. Reconsideration final: $25 billion to $61 billion per year (7% discount rate) 
Boiler Area Source Rule

 Created a new subcategory for seasonally operated boilers

o Required to complete a tune-up every five years, instead of on a biennial basis as 

is required for non-seasonal boilers

 Added temporary boilers to the list of boilers not subject to subpart JJJJJJ.

o To be consistent with the Boiler MACT

 Amending rule to specify that all existing boilers subject to the tune-up requirement 

would have three years (by March 21, 2014) in which to demonstrate initial compliance, 

instead of one year to demonstrate initial compliance.

 Amending the monitoring requirements to allow sources subject to a carbon monoxide 

emission limit the option to install, operate and maintain a carbon monoxide and oxygen 

continuous emission monitoring system.

 Changing the requirement for subsequent tune-ups only for oil-fired boilers equal to or 

less than 5 MMBtu/hr to a tune-up once every 5 years.

 Adding residential boilers and electric boilers to the list of boilers not subject to subpart 

JJJJJJ to clarify that boiler used in residences located at commercial (farms) and 

institutional (universities) facilities are not subject to the rule.

 Revising the definition for “Hot water heater” to include small not water boilers.

 Amending the mercury and CO emission limits for coal fired boilers.

o Mercury limit changing from 4.8 lb/TBtu to 22 lb/TBtu

o CO limit changing from 400 ppm to 420 ppm

 Control costs and benefits (2008$)

o March 2011 final rule

 Costs: $535 million per year

 Benefits: $190 million to $470 million per year (7% discount rate)

o Reconsideration final

 Costs: $490 million per year

 Benefits: unchanged 

06/07/12