EPA Issues Final Rules for Boilers

The U.S. Environmental Protection Agency (EPA) reports that more than 200,000 boilers, process heaters and incinerators will be impacted by a set of Clean Air Act regulations issued on February 21, 2011. Since EPA first proposed the Maximum Achievable Control Technology (MACT) rules in April 2010, several industry sectors have argued the costs of implementing the rules would pose an unreasonable burden on businesses. In response to this criticism, EPA revised the rules in a manner that it believes cuts the cost of implementation by about 50%.

The New Rules
EPA issued in February four sets of final regulations. The first applies to boilers at major sources of toxic emissions. This will impact about 13,800 boilers. The second rule applies to boilers located at smaller sources of emissions, referred to as area sources. About 187,000 boilers are subject to this rule. A third rule applies to commercial and industrial solid waste incinerators, while the fourth sets emission standards for sewage sludge incinerators. Collectively, there are about 300 solid waste and sewage sludge incinerators.

EPA issued the proposed rules in April 2010 and was immediately flooded with some 4,800 comments objecting to provisions in the rules. In the wake of these comments, EPA revised the proposed standards. EPA now estimates that for every dollar spent to cut these pollutants, the public will see $10 to $24 in health benefits. Because the final standards significantly differ from the proposals, EPA believes further public review is required. Therefore, EPA will reconsider the final standards and seek additional public review and comment.

The most controversial of the four rules is the MACT for boilers and process heaters located at major sources of air pollution. EPA made several changes requested by industry, such as creating subcategories of emission limits for certain types of boilers. However, EPA declined an industry request that it adopt a health-based standard that would exempt units from the rule.

For boilers and process heaters located at major sources, the final rule establishes a work practice standard, instead of numeric emission limits. The operator will be required to perform an annual "tune-up" for each unit. Units combusting gases other than natural gas can qualify for work practice standards by demonstrating that they burn "clean fuel," with contaminant levels similar to natural gas.

All new and existing units with a heat input capacity less than 10 million Btu/hr and "limited use" boilers (those that operate less than 10% of the year, as emergency or backup units) also require a work practice standard — and a tune-up once every two years.

For all other existing and new boilers and process heaters located at major sources (including those that burn coal and biomass), the final rule sets numeric emission limits. The rule also establishes emission limits for mercury, dioxin, particulate matter (PM), hydrogen chloride, and carbon monoxide (CO) and requires monitoring to assure compliance with emission limits.

The standards for units located at area sources address emissions of mercury, PM and CO and are bifurcated into standards for new boilers and those for existing boilers. For new boilers, the final rule requires that coal-fired boilers with heat input equal or greater than 10 million Btu/hr meet emission limits for mercury, PM and CO. Biomass and oil-fired boilers with heat input of at least 10 million Btu/hr must meet emission limits for PM. Boilers with heat input less than 10 million Btu/hr must perform a boiler tune-up every two years.

Existing coal-fired boilers with heat input of at least 10 million Btu/hr must meet emission limits for mercury and CO. Biomass boilers, oil-fired boilers and small coal-fired boilers are not required to meet emission limits. They must perform a boiler tune-up every two years to improve combustion efficiency.  This will optimize fuel use and thus reduce emissions of mercury and all other air toxics. All area source facilities with large boilers also are required to conduct an energy assessment to identify cost-effective energy conservation measures.

EPA's changes to the rule and its plans to reconsider portions of it do not appear to have assuaged industry's concerns. Several industry sectors and trade associations have pledged to continue to push EPA for additional revisions. Stay tuned, as this area is being closely watched.