EPA admits making math error in mercury proposal

After being taken to task by critics in the utility industry, U.S. EPA conceded yesterday that it made mathematical errors in newly proposed limits on mercury from coal-fired power plants.

The Utility Air Regulatory Group, a coalition of power companies that often challenges new Clean Air Act rules, recently claimed that "egregious errors" by EPA led to estimates that the cleanest power plants are releasing 1,000 times less mercury than they actually are. The mercury limits are one of the key requirements of the proposed limits on toxic emissions from coal plants, which were proposed in March (Greenwire, March 16).

EPA did err when it calculated what the maximum achievable control technology (MACT) can achieve, but the mistakes aren't as serious as was claimed, air chief Gina McCarthy said in a letter to the industry attorneys yesterday.

Nudging the limit upward to correct the error would allow U.S. coal plants to release an extra 1,000 pounds of mercury per year -- a small fraction of the 29 tons of mercury that the plants now release into the air. After the change, power plants will still need to trap 90 percent of the mercury that is naturally found in the coal they burn, the letter says.

Agency staffers have fixed the mistakes and will show their work to the public this week. They "do not expect this change to have any appreciable impact on the controls that will be needed for compliance," McCarthy wrote.


Many coal-fired utilities argue that the rules are too expensive, and their attorneys have argued that the mathematical error was reason enough to extend the public comment period. EPA estimates that the rule will save tens of thousands of lives each year at a cost of $10.9 billion annually, though industry groups say the cost will be higher.

Thomas Fanning, the president of Atlanta-based utility Southern Co., said during a recent hearing of the House Energy and Commerce Committee that the comment period should be extended. House Energy and Commerce Chairman Fred Upton (R-Mich.) and Sen. James Inhofe (R-Okla.), who leads the Republicans on the Senate Environment and Public Works Committee, echoed those concerns this week by asking EPA to give utilities four months rather than two.

"The current, truncated schedule is insufficient to provide for a thoughtful, deliberative rulemaking process -- especially considering the magnitude of what has been proposed," they wrote along with Rep. Ed Whitfield, the Kentucky Republican who chairs the House Energy and Power Subcommittee.

EPA isn't planning to oblige them, EPA spokesman Brendan Gilfillan said. The math mistakes shouldn't interfere with the agency's schedule for finishing the rules, and there's still no basis for the claims that the final rules will be too difficult or costly for the utility sector to achieve, he wrote in an email.

"More than half of all coal-fired power plants already deploy the widely available pollution control technologies that allow them to meet these important standards," Gilfillan said. "It is long past time to level the playing field and put in place the first-ever national standards for the harmful pollutants emitted by these facilities."

That stance is supported by public health groups and environmentalists, who are pressuring the agency not to back down on its plan to cut pollution from coal plants.

Frank O'Donnell, president of the advocacy group Clean Air Watch, said the complaints about the mercury mistakes were making "much ado about very little."

"This technical adjustment is no reason to delay these critical public health protections," he said in an email. "In fact, this episode shows the system works. EPA strives to base its standards on science and the facts. And that's what it is doing here."

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