EPA Announces Changes to Area Source Rule and Major Source Rule

On March 21, 2011 the U.S. Environmental Protection Agency (“EPA”) published two rules regarding air emissions that pertain to boilers and were specifically designed to reduce emissions of air pollutants.  Those two rules are:

  • Major Source (Boiler MACT) Rule designed to limit emissions from large sources of air pollutants; and 
  • Area Source Rule which reduces boiler emissions from small sources of air pollutants

The boiler Maximum Available Control Technology (“MACT”) Rule applies to boilers located at major sources of hazardous air pollutants (“HAPs”).  A source is considered major if it has the potential to emit 10 tons per year or more of any individual HAP, or the potential to emit 25 tons per year or more of any combination of HAPs.  If the source emits less than this amount, then it is considered a minor source and subject only to the Area Source Rule.  The Boiler MACT Rule achieves emission reductions through a combination of prescribed work practice standards, numeric emission limit reductions, and additional monitoring requirements.  Which of these control technologies applies depends upon the fuel source for the individual boiler. 

Under the rule, owners and operators of certain boilers and process heaters were required to meet Work Practice Standards by March 21, 2012 and install MACT equipment by March 2014.  However, on February 7, 2012, the EPA provided a “no action assurance” (“NAA”) to boiler operators of major source facilities.  Under the NAA the agency can use its discretion in enforcing the boiler MACT requirements.  The NAA will be in effect until December 31, 2012 – giving owner/operators additional time to bring their boilers in compliance with the MACT Rule.

Under the Area Source Rule, coal-fired boilers with heat input equal to or greater then MMBTU/hr, are required to meet new emission limits for mercury, particulate matter and carbon monoxide.  In addition, existing coal-fired boilers with heat input equal to or greater than 10 MMBTU/hr are required to meet reduced emission limits for mercury and carbon monoxide.  Finally, all area source facilities with large boilers are required to conduct an energy assessment to identify cost effective energy conservation measures, and conduct a “tune up” by March 21, 2012.

On March 13, 2012 the EPA issued an NAA for the initial tune up deadline.  Under the NAA, the EPA will exercise its discretion not to pursue enforcement action against sources that fail to complete a boiler tune up by the compliance date of March 21.  The NAA remains in effect for area source boilers until October 1, 2012, or until the effective date of the rule, whichever comes first.

We are strongly advising clients who may be affected to not put off bringing their boilers into compliance with the new rules.  If you feel that your facility may be affected by these new rules and have questions, please don’t hesitate to contact Phillip Hoover at:, or by phone at: (404) 815-3769.

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