Timeline of delay

The long road to controlling mercury emissions from power plants


  • 1990

    The 1990 Clean Air Act requires EPA to prepare for Congress a study of the amount of and health and environmental effects of hazardous pollution from electric utilities the technologies available to control emissions, and the costs of such technologies. As part of that study, Congress asked EPA to determine whether it was "appropriate and necessary" to regulate hazardous pollution from electric power plants.

  • 1997

    EPA completed the "Mercury Study Report to Congress", a massive review of the state of the science on mercury.

  • 1998

    EPA sent the "Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units" to Congress.

  • 2000

    After a two year delay and further study of mercury pollution from power plants, EPA determines that it is "appropriate and necessary" to regulate hazardous air emissions from electric utilities under section 112 of the Clean Air Act and officially lists power plants as a source of hazardous pollution. With this conclusion, EPA is required to issue power plant-specific Maximum Achievable Control Technology (MACT) standards by 2004.

    This finding was immediately challenged by the utility industry. See Utility Air Regulatory Group v. EPA, No. 01-1074 (D.C. Cir. filed Feb. 16, 2000). The 3-judge panel dismissed the challenge for lack of jurisdiction.

  • 2004

    After another four years, EPA proposes to change its conclusion that it is "appropriate and necessary" to regulate power plant hazardous air emissions under Section 112 of the Clean Air Act. EPA also proposes to remove power plants from the official list of hazardous air pollution sources. Instead of MACT standards requiring health-protective emission reductions at each plant, EPA proposes the less protective Clean Air Mercury Rule (CAMR), that defers emission reductions to address mercury pollution for over a decade.

  • 2005

    Against recommendations from health experts and its own findings in the 1998 report to Congress, EPA "delists" power plants as a source of hazardous air emissions. Instead EPA finalizes CAMR, which provides a categorical exclusion from the obligation for the maximum mercury reductions at each power plant and defers reductions to address mercury pollution for over a decade.

  • November 2005

    The State and Territorial Air Pollution Program Administrators (STAPPA) and the Association of Local Air Pollution Control Officials (ALAPCO) release "Regulating Mercury from Power Plants: A Model Rule for States and Localities," in response to their concern that the CAMR rule would not result in adequate reductions in emissions of mercury from coal-fired power plants to protect public health. The document describes two options for state and local governments to develop utility mercury rules more protective of public health and the environment than EPA's regulation.

  • 2007

    By February, 18 states have established more protective emissions limits, which will take effect sooner than will EPA's, and four other states are developing regulations that would do so.

  • 2008

    A unanimous 3-judge panel of the U.S. Court of Appeals for the D.C. Circuit vacates EPA's rule removing power plants from the Clean Air Act list of hazardous air pollution as well as the Clean Air Mercury Rule.

  • 2009

    On February 23, 2009, the Supreme Court denies the Utility Air Regulatory Group's request to review the U.S. Circuit Court of Appeals decision. See UARG vs. New Jersey et. al., No. 08-352.

  • 2010

    A federal district court judge approves a Consent Decree requiring EPA to propose a new rule under the Section 112 protections for air toxics no later than March 16, 2011 and to finalize a rule no later than November 16, 2011.

  • 2011

    EPA finalizes the Mercury and Air Toxics rule (MATS) to regulate mercury emissions from power plants under Section 112 of the Clean Air Act through plant specific MACT standards. This rule replaces the court-vacated CAMR.

  • March 16, 2012

    Industry files a challenge in the D.C. Circuit to the Mercury and Air Toxics Rule.

  • June 20, 2012

    53 Senators, in a bipartisan vote, defeat Senator James Inhofe's resolution to undo the Mercury and Air Toxics rule.

  • October 23, 2012

    Briefs filed in the D.C. Circuit to the Mercury and Air Toxics Rule.

  • December, 2013

    U.S. Court of Appeals for the D.C. Circuit Hears Oral Arguments.

  • April 15, 2014

    A three- judge panel of the U.S. Court of Appeals for the D.C. Circuit upheld the Mercury and Air Toxics Standards in April 2014.