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A Primer on New EPA Rules on Emissions from Boilers

The Environmental Protection Agency issued new rules regulating emissions from boilers at industrial, commercial and institutional sites last month. The rules, which are projected to go into effect by June, are expected to have an impact on more than 200,000 existing boilers across the U.S.

The rules divide existing boilers into two categories based on the potential amount of air toxics emitted. Major source boilers have the potential to emit 10 or more tons per year (tpy) of any single air toxic or 25 tpy or more of any combination of toxics. Boilers that have the potential to emit less than 10 tpy of a single toxic or 25 tpy of any combination are classified as area sources.

Area sources make up the majority of impacted existing boilers – estimated at 187,000 at 92,000 facilities. The new rules cover boilers that burn coal, oil, or biomass, or non-waste materials, according to a summary from the EPA. Natural gas-fired boilers are not included in the regulations, nor are boilers that burn solid waste.

The primary impact of the new rules on area source boilers is in testing and reporting. All area source facilities with large boilers (heat input capacity of equal or greater than 10 million BTU per hour) will be required to conduct an energy assessment to identify "cost-effective energy conservation measures," according to the EPA. In addition, biomass boilers, oil-fired boilers and small coal-fired boilers (heat input capacity less than 10 million BTU per hour) will have to undergo a boiler tune-up every two years.

Large coal-fired boilers will be required to meet set emissions standards for mercury and carbon monoxide. Other area source boilers will not have to meet set emissions standards.

Boilers at major source facilities will have to meet more stringent requirements for air toxic emissions. The new rules create 15 different subcategories of major source boilers, and include specific requirements for each subcategory.

For example, natural gas- and refinery gas-fired units, small units, and "limited use" boilers will have to meet newly established "work practice standards" as opposed to numeric emission limits. All other existing and new boilers will be required to meet newly established numeric limits for mercury, dioxin, particulate matter, hydrogen chloride and carbon monoxide.

Additionally, new reporting and tune-up requirements have been established for all major source boilers.

The EPA estimates 13,840 boilers and process heaters in the U.S. qualify as "major sources of air toxics emissions."

More information on the new air toxics standards for industrial, commercial, and institutional boilers and process heaters may be found at

NAHAD will provide more details on the impact of these new standards on distributors and manufacturers in coming issues of Hose Connections.