Mercury and Air Toxics Standards Proposed for Power Industry

On Wednesday, March 16, the U.S. EPA signed proposed new national emission standards for hazardous air pollutants (NESHAP) in response to a 2009 court settlement to replace the vacated Clean Air Mercury Rule (CAMR). The proposed rule is expected to significantly affect coal- and oil-fired power plants that have not implemented at least current NSPS-level emissions control equipment. These regulations are developed under Section 112 of Clean Air Act due to a December 2000 EPA decision that regulation of hazardous air pollutants (HAP) from coal- and oil-fired electric utility units is “appropriate and necessary.” Notably, that same 2000 decision did not find regulation of HAP from natural gas-fired electric utility boilers to be appropriate or necessary and such boilers are not included in the proposed rule.

EPA anticipates benefits to public health and welfare, which it values at $59 - $140 billion a year to outweigh costs of approximately $11 billion per year. Many affected facilities will be required to upgrade existing controls or install new controls such as scrubbers, fabric filters, activated carbon injection, electrostatic precipitators, and dry sorbent injection. Further, numerous older boilers subject to the rule are expected to shut down rather than add the required pollution controls. Regional differences will determine the threshold size that is not cost effective to retrofit and instead retire, but coal units less than 100 MW are at high risk and coal units less than 200 MW are at medium risk.

EPA agreed to a final rule date of December 2011 in the court settlement, meaning compliance will be required by approximately December 2014, with the potential for a 1-year extension as provided under EPA’s general provisions for Section 112 regulations.

In addition to the proposed NESHAP, EPA has also issued proposed NSPS limits for PM, SO2 and NOX based on a reconsideration of the 2006 NSPS Subpart Da (electric utility boilers) and minor corrections to other boiler NSPS (Subparts D, Db, and Dc).

EPA expects the new standards to affect approximate 1200 coal-fired and 150 oil-fired units at approximately 525 power plants. The new requirements include: 

  • Emission limits for mercury, PM, and hydrochloric acid for coal-fired units 
  • Emission limits for total metals, HCl, and HF for oil-fired units
  • Alternative standards for certain subcategories of power plants
  • Work practice requirements to limit organic air toxics, including dioxin and furan

EPA will accept public comment on the rule for 60 days following its publication in the Federal Register; public hearings will also be held. For more information, visit http://www.epa.gov/airquality/powerplanttoxics or contact your local Trinity office at (800) 229-6655.