4 The record articles

Boiler MACT…Yes…No…Maybe?

Posted: June 10th, 2011

Author: All4 Staff 


On March 21, 2011, U.S. EPA published a final rule regulating hazardous air pollutant (HAP) emissions from boilers and process heaters located at major sources of HAP emissions (Boiler MACT). On that same date, U.S. EPA also published a notice that it was going to initiate a reconsideration process for several portions of the rule because U.S. EPA believed that the public should have the opportunity to comment on some of the last-minute changes that were made to the rule in order to meet the court-ordered deadline for finalizing the rule, including changes that were made to the boiler categories and boiler emission limitations.

Because U.S. EPA has an abundance of comments to evaluate, several industry groups have filed petitions for judicial review of the rule and litigation against U.S. EPA is pending. U.S. EPA published notice in the Federal Register on May 18, 2011 that it was delaying the effective date for the final Boiler MACT until such a time as the proceedings for judicial review are completed or until U.S. EPA completes its reconsideration of the rule, whichever is earlier. Without an effective date, the Boiler MACT will remain unenforceable until such time as it becomes effective. In other words, by delaying the effective date of the Boiler MACT, U.S. EPA essentially figured out a clever way to meet the court-ordered deadline for finalizing a Boiler MACT rule and then quickly take the rule off the books to allow the agency additional time to consider the public’s comments. Without an effective date, it is as if the Boiler MACT does not exist.

Limits Properly Set or Flawed Logic?

Many questions surround the logic that U.S. EPA used to develop the emission limits contained in the Boiler MACT. One potential flaw identified by those petitioning U.S. EPA for judicial review of the Boiler MACT is the establishment of emissions limitations using data collected from boilers that fire fuels that would now be classified as non-hazardous secondary materials (NHSM). In other words, based on U.S. EPA’s new definition of a solid waste (also published in the Federal Register on March 21, 2011), some boilers should be classified as Commercial and Industrial Solid Waste Incinerator (CISWI) units. Combustion units that have historically fired fuels such as tire derived fuel (TDF), wastewater treatment plant (WWTP) residuals, used oil, and resinated wood (e.g., plywood, oriented strand board, etc.) could potentially be subject to the New Source Performance Standards or Emissions Guidelines for CISWI units published in 40 CFR Part 60, Subparts CCCC and DDDD, respectively. Some commenters believe that the data collected from these boilers should not have been used to establish emission limits under the Boiler MACT, and instead should have been used to establish emission limits for CISWI units. It’s worth noting that the effective dates of the amended CISWI Rules were also delayed in the May 18, 2011 Federal Register notice. However, the effective date of the definition of solid waste rule (DSW Rule) was not.

By using U.S. EPA’s new DSW Rule to question the data that U.S. EPA used to develop emission limits for the Boiler MACT, commenters are able to draw some much needed attention to some of the seemingly absurd assumptions that U.S. EPA made when developing the DSW Rule. For example, a boiler firing TDF made from tires that are removed from vehicles and managed under an approved collection program would be subject to the Boiler MACT because, under that scenario, U.S. EPA determined that TDF made from such tires is not discarded and therefore not considered a waste. However, a boiler firing TDF that contains tires reclaimed from a pile or defective tires that were never used on a vehicle would be classified as an incinerator and subject to the CISWI Rules because only those tires that are removed from vehicles and managed under an approved collection program are not considered discard and therefore not considered to be a waste. TDF purchased from one fuel supplier could therefore be a solid waste while TDF purchased from another fuel supplier might not be a solid waste. Because the DSW Rule did not exist when U.S. EPA was evaluating emissions data to establish new emission limits under the Boiler MACT and CISWI rules, how did U.S. EPA determine whether a combustion unit was a “boiler” or a CISWI unit? How could U.S. EPA have determined whether the emissions data collected were representative of a boiler or a CISWI unit without evaluating each fuel stream based on the new DSW Rule? Did U.S. EPA develop new emission limits for boilers using data collected from CISWI units? If so, the data should have been used to establish emission limits under the CISWI Rules.

How Long Will the Effective Date Be Delayed?

U.S. EPA cannot predict how long the reconsideration process will last, but one U.S. EPA employee has told ALL4 off-the-record that he believes the reconsideration process could last a year or more. Although the effective dates of the new Boiler MACT and CISWI Rules have been postponed, do not automatically assume that the compliance dates associated with each rule will be changed as part of the reconsideration process. Unless the changes to these rules are significant, U.S. EPA may not see the need to postpone the compliance dates. So, should you sit around and wait to see what happens with the Boiler MACT before taking any action? You certainly could, but we don’t recommend it. Here’s a brief list of some of the things you can be doing right now to prepare yourself for the final (or is it final final?) publication of the Boiler MACT:

  • Review the DSW Rule and determine whether any of the fuels that you currently burn are considered to be solid waste. U.S. EPA clearly stated in the Federal Register that the DSW Rule was no longer open for comment and would not be reconsidered. If you determine that you are burning a NHSM that is a solid waste, your combustion unit will be subject to the CISWI Rules unless you permanently cease firing the waste six months before the compliance date.
  • Evaluate the emissions from your combustion unit. Conduct emissions testing, if needed, while firing your worst-case fuel (or fuels) for comparison to the emission limits in the Boiler MACT and/or CISWI Rules. Although U.S. EPA may change some of the numerical emission limits during the reconsideration process, the pollutants regulated by the rules are not likely to change. You should be actively gathering as much information as possible about your combustion units so that you can hit the ground running once the reconsideration process is completed. Remember, U.S. EPA estimates that there are over 13,000 existing boilers that will be subject to the Boiler MACT once it becomes effective, and every facility will be rushing to comply with this rule at the same time. Outside resources could quickly become limited.
  • Begin developing relationships with control device vendors and/or boiler optimization companies. Develop an understanding of the technologies and techniques available to reduce emissions of the pollutants regulated by the Boiler MACT. Develop an understanding of the capital costs, operating costs, and limitations associated with each emission reduction technology and technique.
  • Evaluate the cost and availability of alternative fuels. Switching fuels may subject your combustion unit to emission limitations that can more easily and cost effectively be achieved.
  • Be creative and evaluate other options potentially available to your facility. Can you make process improvements to reduce steam demand enough to decommission one of your boilers? Given the choice, most of the companies that ALL4 works with would rather spend their money on making process improvements than spend it on environmental control systems for older boilers.
  • Perform your required energy audit now.


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