In response to federal court orders requiring the issuance of final standards, the U.S. Environmental Protection Agency (EPA) issued final Clean Air Act standards for boilers and certain incinerators.(Read the EPA rulemaking.)
The agency immediately said it would reconsider the final standards to seek additional public review and comment.
EPA said that because the final standards significantly differ from the proposals, it believes further public review is required. EPA said it will reconsider the final standards under a Clean Air Act process. The agency's reconsideration will cover the emissions standards for large and small boilers and for solid waste incinerators. EPA will release additional details on the reconsideration process in the near future to ensure the public, industry and stakeholders have an opportunity to participate.
"The Clean Air Act standards we are issuing today are based on the best available science and have benefitted from significant public input," said Gina McCarthy, assistant administrator for EPA’s Office of Air and Radiation.
The rules set the following emission limits for area source boilers.
For existing coal-fired boilers with heat inputs greater than 10 MMBtu/h, mercury emissions are limited to 0.0000048 lb and carbon monoxide emissions are limited to 400 ppm by volume on a dry basis corrected to 7 percent oxygen.
For new coal-fired boilers with heat inputs greater than 30 MMBtu/hr, the limit for particulate matter is 0.03 lb, for mercury it is 0.0000048 lb and for carbon monoxide it is 400 ppm by volume on a dry basis corrected to 3 percent oxygen.
For new coal-fired boulers with heat inputs that are greater than 10 and less than 30 MMBtu/h, the emissions limit is 0.42 lb for particulate matter, 0.0000048 lb of mercury and 400 ppm of carbon monoxide.
For new biomass-fired boilers that have heat inputs greater than 30 MMBtu/h, the particulate matter limit is 0.03 lb. For boilers with heat inputs greater than 10 but less than 30 MMBtu/h the particulate matter limit is 0.07.
For new oil-fired boilers that have heat inputs greater than 30 MMBtu/h, the limit on particulate matter emissions is 0.03 lb. For boilers greater than 10 and less than 30 MMBtu/h heat input the limit is 0.03 lb.
The emission limits for mercury and CO apply only to boilers in the coal subcategory; the emission limits for existing area source boilers in the coal subcategory are applicable only to area source boilers that have a designed heat input capacity of 10 million MMBtu/h or greater.
For boilers that burn any solid fossil fuel and no more than 15 percent biomass on a total fuel annual heat input basis, the boiler is in the coal subcategory. For boilers that burn at least 15 percent biomass on a total fuel annual heat input basis, the unit is in the biomass subcategory. For boilers that burn any liquid fuel and is not in either the coal or the biomass subcategory, the unit is in the oil subcategory, except if the unit burns oil only during periods of gas curtailment.
EPA said it also is requiring all biomass-fired and oil-fired area source boilers to implement a tune-up program as a management practice.
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