An EPA Potboiler: Clean Air Retreat?

03/09/2011 12:21 pm ET | Updated May 25, 2011
  • Bill Chameides Dean, Duke University's Nicholas School of the Environment

EPA has cut costs by amending its rules for boiler emissions. Do we pay it back in air-quality costs?

The Environmental Protection Agency has been under concerted attack by members of the new Congress seeking to strip the agency of regulatory powers and cut its budget. Makes me wonder: are EPA's new, weakened rules on hazardous air pollutants intended as a peace offering to the anti-EPA forces? Or possibly a white flag?

The Official Story on the New Emissions Rules for Boilers

The official EPA story would appear to quash any notion of backpedaling. According to the New York Times, "EPA officials said on Wednesday that the altered rule would cost half as much as the previous proposal while achieving virtually the same health benefits." EPA's own press release states, less definitively, that the final standards will "achieve significant public health protections through reductions in toxic air emissions, including mercury and soot, but cut the cost of implementation by about 50 percent from an earlier proposal issued last year."

Getting the same or similar health benefits for lower costs. I'd vote for that. But is that what we're really getting? Let's see.

The Backstory on EPA's Boiler Rules

Boilers are enclosed devices that combust fossil fuels or biomass usually to produce hot water or steam. They're pretty commonplace -- the hot water and steam in my old New York apartment, for example, came from a boiler in the basement. Considerably larger ones are common in industrial and commercial facilities.

As with all combustion, boilers generate air pollutants. These include impurities in the fuel (mercury, lead) and partially combusted material, like particulate matter (PM) or soot, as well as carbon dioxide.

Last April EPA proposed rules that would have brought the country's roughly 200,000 large and small industrial boilers into compliance with the Clean Air Act. These rules, which were some three years in the making, were designed to address some of the worst air pollutants, including mercury, lead, and soot, which are linked to serious health problems from developmental disabilities to heart disease and cancer.

In the ensuing months EPA received an outpouring of complaints from industry (see here and here) and members of Congress (see here) that the rules were overbearing. Not so, responded EPA, whose analysis showed that the rules would reap health benefits far in excess of the cost of emission controls.

But times changed. Two weeks ago EPA released its final rules and there are notable differences.

EPA's Proposed Rules: Then and Now

The table below provides a cursory look at the "major source"* rule for boilers.

EPA's Rules for Boiler Emissions, Apr. 2010 vs. Feb. 2011

Proposed Rule

(April 2010)

Final Rule

(February 2011)

% Change
Number of major units

     Existing 13,555 13,840  
     New        46        47  
Annual cost (overhead and maintenance) 

$2.9 billion

$1.4 billion

Emission reductions

(in tons/year except

where otherwise noted)





     Mercury (Hg)


            1.4 -81%
     Non-mercury metals     3,202


     Hydrogen chloride (HCl)



     Particulate matter




     Volatile organic

     compounds (VOCs)



+ 4x
     Sulfur dioxide (SO2)



EPA's rules for boilers defined as "major sources." The middle columns list EPA's estimates of emission reductions (the lower the number the laxer the rule). The far right column shows the percentage difference (the more negative the number, the less emissions reductions from the new rule). Note that existing units have looser standards (i.e., emit more pollutants) than new sources. 

Consistent with EPA's press release, the new rules bring considerable savings -- a halving of annual costs. And while most emission limits were loosened, not all were.

There is little change for PM or soot. And for some pollutants -- like volatile organic compounds (VOCs) and sulfur dioxide (SO2) -- the new rules actually remove more.

For metals like lead and arsenic, the final rules appear to allow emissions to increase by about 20 percent -- not too bad, some might argue, given the price break between the rules.

New Rules Appear to Give Up the Ghost on Mercury and Dioxin

But the story changes for mercury and dioxin. Despite the fact that EPA noted mercury as one of the targeted pollutants, the final rule for major sources:

  • allows five times more mercury to be emitted than the proposed rule, and

  • cuts only three percent of the dioxin emissions that the proposed rule had first mandated.

After utilities, boilers are the largest source of U.S. mercury emissions. According to EPA, in toto the proposed rules for boilers and incinerators would have cut overall emissions by 50 percent, the final rules, by a mere 10 percent.

In revamping its boiler rules, it appears that EPA has decided to hold the line for a number of pollutants, maybe even tried a little end run around by quietly ratcheting down the emissions of others. But in the case of the highly toxic metal mercury, the agency seems to be in punt formation.



* The analysis in this post pertains only to the major source rule. Major sources, as defined by EPA, have the potential to emit more than 10 tons per year of a single pollutant or 25 tons per year of any combination of toxics. Individual pollutants with emission limits include mercury, dioxin, particulate matter (as a surrogate for non-mercury metals), hydrochloric acid (as a surrogate for acid gases) and carbon monoxide (as a surrogate for non-dioxin organic air toxics).

The final rule, still in draft form, may differ from what will be published in the Federal Register. The rule used a revised methodology to calculate emission reductions
that may or may not be different from the methodology used in the
proposed rule.

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