Client Alerts
May 03, 2011

Comment period opens on EPA's proposed Mercury and Air Toxics Rule for Coal-Fired Power Plants

Stites & Harbison, PLLC, Client Alert, May 3, 2011

On May 3, 2011, the Environmental Protection Agency (“EPA”) published a federal register notice proposing a rule that would limit the emissions of mercury and other air toxics from power plants.1 This rule would apply to new and existing coal- and oil-fired electric utility steam generating units (“EGUs”). The proposed rule replaces the Clean Air Mercury Rule that was vacated by the DC Circuit Court in 2008 in the case, New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 2008). In addition, EPA is proposing a new source performance standard for new coal- and oil-fired EGUs for particulate matter (PM), sulfur dioxide (SO2) and nitrogen oxide (NOx).

Interested parties have until July 5, 2011 (sixty days from publication of the proposed rule in the federal register) to provide comments to EPA on the proposed rule. EPA is also planning to hold public hearings on the proposed rule on May 24, 2011 in Chicago, IL and in Philadelphia, PA. EPA will also hold a public hearing in Atlanta, GA on May 26, 2011.

Who is Covered by the Proposed Rule?

EPA’s proposed rule will apply to new and existing coal- and oil-fired EGUs with capacities of 25 megawatts or greater. EPA estimates that approximately 1,350 EGUs will be affected by the proposed rule, 1,200 coal-fired units and 150 oil-fired units. Included within the coal-fired units covered by the rule are those that burn coal, coal refuse, or a synthetic gas derived from coal or petroleum coke (i.e. those using integrated gasification combined cycle configurations). Natural gas power plants are not affected by the proposed rule.

What Does the Proposed Rule Require?

For coal-fired power plants, the proposed rule will establish numeric limits on mercury emissions that would prevent 91% of the mercury found in coal from being released to the air. The rule would also establish numeric limits for hydrochloric acid (as a surrogate for acid gases with an alternate surrogate of SO2) and particulate matter (as a surrogate for other, non-mercury, metallic toxic pollutants with an alternate surrogate of total metal air toxics). Additionally, the rule will require the implementation of work practice standards to limit the emissions of organic air toxics such dioxins. Oil-fired sources will be subject to numeric limits for acid gases and total metal air toxics and work practice requirements for control of organic air toxics

As required by Section 112 of the Clean Air Act, these limits will be set at a level that is at least as stringent as the average levels achieved by the top 12% of existing coal-fired EGUs. EPA anticipates that affected sources will install new equipment to comply with the requirements of this rule. The compliance date under the proposed rule is 2014, with the opportunity for affected sources to seek an additional year if necessary.

What’s Next?

EPA is accepting public comment on the proposed rule until July 5, 2011. In addition, EPA is holding three public hearings, in Atlanta, GA, Chicago, IL, and Philadelphia, PA to take testimony on the proposed rule. EPA is obligated under a Consent Decree of the D.C. Circuit Court of Appeals to issue the final rule in November, 2011, so it is likely that process for preparing and publishing a final rule will move quickly.

1For additional information regarding the proposed rule, see EPA's website at

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