Regulating Mercury: A Crucial Step Forward
Regulating Mercury: A Crucial Step Forward

After more than 20 years of deliberation, the U.S. Environmental Protection Agency (EPA) finally issued the Mercury and Air Toxic Standards (MATS), the first national standards in the U.S. to regulate power plant emissions of mercury and other toxic air pollutants.  The 1990 Clean Air Act mandated the control of mercury and other pollutants emitted from power plants.  Nonetheless, it took 20 years to finalize the regulations that are expected to provide $37-90 billion dollars in health and economic benefits by 2016.1

Given four years to comply, power plants will be required to deploy pollution control technologies to prevent 90 percent of mercury emissions and 88 percent of acid gas emissions.2   About 60 percent of the 1,400 coal-fired power plants in the U.S. already meet these standards. With an estimated annual cost of $11 billion dollars, the new standards require that the rest do the same.3  Some believe that the cost- benefit ratio does not justify these new regulations and that they will force the closure of many power plants, threatening local electricity supplies.

This analysis will examine health and environment impacts of mercury and air pollutants, pollution control technologies, national and international mercury regulations and critiques of the politicization of mercury regulation.

Health and Environment Impact of Mercury and Air Pollutants

Mercury is a naturally occurring element. One-third of mercury emissions come from natural sources, such as volcanic eruptions. The remaining two-thirds of emissions come from anthropogenic (human-caused) sources. Coal plants are the biggest world-wide source of anthropogenic mercury emissions. The numbers are not precise because mercury can be re-emitted from land and water sources. Much of the mercury circulating in the air today was released years ago.4

Mercury is a neurotoxin. Mercury from power plants is problematic when it turns into methyl mercury and is consumed by fish, and thus consumed by humans in large quantities. High dosages of methyl mercury to fetuses in the womb have been known to cause mental retardation, cerebral palsy, deafness, and blindness. Sensory and motor impairments as well as cardiovascular and immune system problems are other potential side effects. High dosage poisoning in the U.S. is rare, but chronic low dosage exposure is relatively common and most harmful to young children.5

Most humans are exposed through eating contaminated fish and shellfish. The CDC reports that six percent of women of childbearing age are exposed to levels of methyl mercury that could put their babies at risk. FDA guidelines recommend that pregnant and nursing women limit their fish intake.6

The EPA estimates that the new Mercury and Air Toxic Standards will prevent up to 17,000 premature deaths annually,7 as well as 100,000 heart attacks and asthma attacks.8

Pollution Control Technologies

There are many technologies used by coal-fired power plants around the world to reduce emission of mercury and other pollutants. For instance, coal washing can reduce the mercury content of coal, but it will not remove all of the mercury. Depending on the type of coal and washing process, efficiency ranges from 3 – 78 percent, with a mean value of 20-30 percent. Improved efficiency and reliability of the plants compensates for the extra costs of cleaning the coal.9

Air pollution control devices are another cost-effective way to reduce mercury emission because they also remove other pollutants, such as nitrogen oxides (NOx), sulfur dioxide (SO2) and dust. Electrostatic precipitators (ESP) and fabric filters (FF) reduce dust emissions from flowing gas using an electrostatic charge and filters bags respectively.  Flue gas desulphurization (FGD) removes SO2 by applying a wet scrubbing solution in vessel before it is emitted into the air. Selective catalytic reduction (SCR) removes NOx through the use of a catalyst that converts NOx into N2 and water.10  ESP, FGD, FF, and SCR all remove mercury as well.

A fabric filter or ESP removes 50 percent of the mercury. When combined additional technologies, mercury emissions are usually low enough to meet most worldwide standards. In a new plant that uses SCR, FGD and FFs, mercury is reduced to the proper levels, without any additional charges. Many European plants have ESP or FGD, but do not have SCR devices. It costs about two million euros to install SCR devices into an existing plant.  As of 2005, one-third of power-generating facilities used FGD. By 2015, the EPA expects that two-thirds of U.S. installations to use FGD.11  While in China, by 2008, 95 percent of power plants had installed ESP and by 2009, 71 percent had installed FGD.12

If a plant does not already use an air pollution control devices, it costs $10 million Euros for an ACI device and a fabric filter. Activated Coal Injection (ACI) is a device solely used to remove mercury. Powdered activated carbon is injected into the flue gas duct work.  There it vaporizes the mercury, which is collected in the fly ash of the facility’s particulate collection device. This is the most established system for reducing mercury, with an efficiency rate of 90 percent. This system can be used on its own or in combination with one of the above technologies.13

Global Context: How is Mercury Regulated around the World?

An estimated 4,400 to 7,500 metric tons of mercury are emitted annually. The U.S. is the third highest country for man-made mercury emissions, emitting about three percent of the global total. About two-thirds of mercury emitted by the U.S. enters into the global cycle.14

Negotiations are underway since 2003 among 120 countries to create a global, legally-binding, treaty to regulate mercury. The treaty is expected to be completed by 2013.15  The agreement will reduce supply/demand, decrease emissions, and create an environmentally-sound system to manage mercury-containing waste. 16

China uses and releases more mercury and SO2 than any other country in the world. In fact, China and Kyrgyzstan are the only two countries in the world that still mine mercury. Mercury is imported to make plastics from coal and to manufacture batteries. The amount of mercury in batteries is decreasing though because U.S. and European consumers banned the import of batteries with high mercury content.17    The Chinese government is working with the National Resource Defense Council and other NGOs to reduce mercury use, but few regulations exist. The government has standards for air pollution, but they are often not met.

In the Europe Union, the 1999 Gothenburg Protocol, the 2008 IPPC Directive (Integrated Pollution Prevention and Control) and the 2010 Industrial Emissions Directive require member states to use the best available technologies to reach specific emission limit value for SO2, NOx and dust. Mercury abatement is not required, but would be reached as a byproduct of the use of air pollution control devices.18

In the United States, hazardous air products have been regulated since 1970 through the Clean Air Act. The act was amended in 1990 to mandate hazardous air products be limited using Maximum Achievable Control Technology (MACT).19  In 2005, the EPA passed the Clean Air Mercury Rule (CAMR) to cap and reduce emissions from coal fired power plants. Power plants were removed from the list in 2008 by a federal court stating that the standards were not strong enough. The new Mercury and Air Toxic Standards replaced CAMR.20

Critics: Mercury Regulations are not Worth the Cost

In 2005, the CATO Institute published an article “The Political Economy of Mercury Regulation” that highlighted the problems and politics associated with regulating mercury.  The article supported the CAMR’s market-based approach to regulating mercury.21 Overall level of mercury is capped, but companies can trade emissions rights to achieve this goal in the least costly manner. The article highlights flaws in CAMR that are also applicable to MATS.

The EPA does not require legislation to have a requirement whose benefits exceed the costs. Furthermore, CATO believes that many of the benefits are overstated. The articles finds fault in the National Research’s Council Statement that six percent of pregnant women could be exposed to high enough levels of mercury to impact the development of their babies. They found that the reference dose of mercury was actually a lot lower than the blood mercury level that results in significant adverse health outcomes in children. No probability was given by the scientists in their estimates of number of children born with problems due to mercury; hence the paper concludes that the problem is overstated. CATO concludes that the increases in IQ due to decreased mercury emissions are not worth the cost of implementing the regulations.


While there are those that debate the science, regulatory agencies around the world have decided that the science shows that mercury emissions need to be regulated. Fortunately, there are many different air pollution control devices that remove mercury along with other toxic chemicals that produce acid rain and lead to a whole variety of environmental and health problems. Many states in the U.S. (as well as in many European countries) recognize this and have taken the lead in cleaning up power plants emissions. The U.S. federal government is finally asserting its leadership and demands that power plants in the rest of the states follow suit.

Pollution is a global problem. Mercury emissions do not only affect the local area, but can get into the air and travel around the globe. Pollution in China impacts air quality in the United States, Japan, and Europe, etc… A global policy to regulate mercury emissions is being developed and will hopefully be passed by many countries around the world. Meanwhile, individual countries should examine the new U.S. policy and see if they can customize it to their own circumstances.

1  “Toward Healthier Air.” The New York Times. December 21, 2011.
3  Broder, John M. ” E.P.A. Issues Rule Limiting Mercury Emissions.” The New York Times. December 21, 2011.
4  “Mercury Emissions: The Global Context.” The Environmental Protection Agency.
5  “Regulating Mercury from Power Plants: A Model Rule for States and Localities emissions from coal-fired power plants.” State and Territorial Air Pollution Program Administrators (STAPPA) and Association of Local Air Pollution Control Officials (ALAPCO). November 2005.
6  Ibid.
7  Broder, John M. ” E.P.A. Issues Rule Limiting Mercury Emissions.” The New York Times. December 21, 2011.
8  Tracy, Ryan and Solomon, Deborah. “EPA Sets Cuts in Plant Emissions.” The Wall Street Journal. December 22, 2011.
9  Weem, André Peeters. “Reduction of mercury emissions from coal fired power plants.” Working Group of Strategies and Review, 48th Session. 11-15 April 2011, Geneva.
10  Ibid.
11  Ibid.
12  Wang, Shuxiao. “Mercury emissions from coal-fired power plants in China.” Presentation to the UNEP INC2 Technical Meeting.
14  “Mercury Emissions: The Global Context.” The Environmental Protection Agency.
15  “Mercury Negotiations Move Forward Towards Global Treaty.” United Nations Environment Programme. November 3, 2011.
16  “Global mercury regulation: one step forward.” Bridges Trade BioRes, Volume 8. Number 18. October 17, 2008.
17  “NRDC Fights to Stop Mercury Pollution in China: China is Cornerstone in Solving Global Mercury Problem.” April 2007.
18  Weem, André Peeters. “Reduction of mercury emissions from coal fired power plants.” Working Group of Strategies and Review, 48th Session. 11-15 April 2011, Geneva.
19  “Regulating Mercury from Power Plants: A Model Rule for States and Localities emissions from coal-fired power plants.” State and Territorial Air Pollution Program Administrators (STAPPA) and Association of Local Air Pollution Control Officials (ALAPCO). November 2005.
20  “Clean Air Mercury Rule.” Environmental Protection Agency. March 16, 2011.
21  Gayer, Ted and Hahn, Robert. “The Political Economy of Mercury Regulation.” REGULATION. SUMMER 2005.

*Picture of the power plant:
* Picture of fish

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