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Emissions Standards for Boilers and Process Heaters and Commercial / Industrial Solid Waste Incinerators


August 23, 2016 - EPA finalizes reconsideration of clean air standards for area source industrial, commercial and institutional boilers.

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On December 2, 2011, EPA proposed changes to the March 2011 Clean Air Act emissions standards for large and small boilers and incinerators that burn solid waste. These standards cover more than 200,000 boilers and incinerators that emit harmful air pollution, including mercury, cadmium, and particle pollution.

Boilers burn natural gas, coal, wood, oil, or other fuel to produce steam. The steam is used to produce electricity or provide heat. Process heaters heat raw or intermediate materials during an industrial process. Boilers and process heaters are used at wide variety of facilities and may stand alone.

  • EPA's proposed standards will control toxic air emissions from boilers located at large and small sources of air toxics.
  • These rules are developed under sections 112 and 129 of the Clean Air Act, two provisions that target toxic air pollution.
  • Under these sections, EPA is required to set technology-based standards for toxic air pollutants, reflective of levels achieved by the best performing existing sources.
  • There are more than 1.5 million boilers in the U.S.
  • For 86 percent of all boilers in the United States, these rules would not apply, because these boilers burn clean natural gas at area source facilities and emit little pollution.
  • For almost 13 percent of all boilers in the United States, EPA’s standards would continue to rely on practical, cost-effective work practice standards to reduce emissions.
  • For the highest emitting 0.4 percent of all boilers in the United States, including boilers located at refineries, chemical plants, and other industrial facilities, EPA is proposing more targeted revised emissions limits that provide industry practical, protective, cost-effective options to meet the standards.

Incinerators burn waste to dispose of it. Some recover energy. EPA has established emissions standards for commercial and industrial solid waste incinerators (CISWI). There are 95 solid waste incinerators that burn waste at commercial or industrial facilities. These standards will reduce emissions of harmful pollutants including mercury, lead, cadmium, nitrogen dioxide and particle pollution.

Boiler and incinerator regulations are closely related because similar units may be considered boilers or incinerators based on whether or not they burn solid waste materials. EPA is also proposing changes to how to determine which non-hazardous secondary materials would be considered solid waste and which would be considered fuel. This distinction would determine whether a material can be burned in a boiler or whether it must be burned in an incinerator. More information


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