Coal is a sedimentary rock made from the compressed remains of ancient swamp plants. It is a fossil fuel widely used for heat and electricity in the US and abroad. Although it provides a seemingly cheap energy source, coal harms human health at every stage of its life cycle – except when it is left in the ground.
Where does coal come from?
Coal seams are abundant in the US. Wyoming leads the nation in coal production, accounting for approximately 40% of the coal that is mined in the US. Other top-producing coal states are West Virginia, Kentucky, Pennsylvania, and Montana. Coal is mined in 26 states, and total US production was just over 1,085 million short tons in 2010. Coal is found worldwide. The top 5 coal-producing countries are China, the USA, India, Australia, and South Africa.
How much coal do we use?
Based on preliminary data and estimates for the first quarter of 2013, U.S. coal exports, which had been steadily growing since 2009 on an annual basis, were down 1.3 million short tons compared with the same period in 2012. Coal plants generated 42% of the electricity produced in the US in 2011. Coal provides a larger share of our electricity supply than any other single source. In recent years, the share of coal-powered electricity has been declining, while that of natural gas has been on the rise–in 2011, natural gas provided about 25% of the electricity in the US. That share is expected to rise in coming years due to falling prices of natural gas and other factors.
Coal and mercury
Mercury is a naturally occurring element present in geologic formations, including coal. When coal is burned in power plants, this toxic element is released into the atmosphere. From there, it can travel hundreds of miles in clouds and falls to the earth in the form of rain. Through this process, mercury enters oceans, rivers, and lakes, and their corresponding aquatic ecosystems. Mercury accumulates in fish, where it is consumed by people.
Mercury is a potent neurotoxin that damages the brain, heart, kidneys, and lungs. It is estimated that 1 in 6 women of childbearing age in the US have blood mercury levels that could damage the developing brain of her fetus. Coal fired power plants are the largest source of airborne mercury emissions in the US. The bulk of this pollution could be eliminated with widely available pollution control devices. The societal cost of mercury pollution in fish has been estimated by researchers at Mount Sinai School of Medicine to be $8.7 billion annually due to lost IQ and productivity.
Coal and other health effects
In addition to mercury, coal combustion releases a slew of dangerous pollutants into the air, including sulfur dioxide, nitrogen dioxide, and particulate matter. Coal fired power plants contribute to the formation of ozone, which, in the presence of heat and sunlight, is created by chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs). These pollutants can travel hundreds of miles, crossing state lines and damaging air quality far from their original source. Exposure to these pollutants in the ambient air at levels common in the US have been linked to significant health problems: asthma attacks, asthma development, chronic obstructive pulmonary disease, lung cancer, stroke, heart disease, and heart attacks. Many of these pollutants can be reduced at the smokestack through the installation of modern, readily availably pollution control technology.
Coal and climate change
Coal combustion produces more air pollution, and more planet-warming carbon dioxide emissions in particular, than other fossil fuel energy sources such as natural gas. It is a “carbon-intensive” fuel, accounting for approximately 20% of all greenhouse gas emissions, worldwide. In the US, coal accounts for 27% of all greenhouse gas emissions. This means that coal combustion for electricity is a major driver of US greenhouse gas emissions. Limiting carbon dioxide emissions from coal plants is key to reducing our global contribution to greenhouse gases. EPA’s proposed Carbon Rule uses provisions of the Clean Air Act to limit carbon dioxide emissions from power plants in the future.
Coal ash: a toxic legacy
After coal is burned, a waste product laced with toxic chemicals remains. Each year, 140 million tons of this toxic waste, or coal ash, is produced. It is disposed of in ponds, landfills, and abandoned mines. Coal ash contains neurotoxic, carcinogenic, and otherwise poisonous substances such as arsenic, lead, and hexavalent chromium. It is not regulated by any federal agency, and state regulations governing its disposal are lax or nonexistent. Inadequately secured coal ash disposal sites can leak or spill, endangering surrounding communities and contaminating groundwater. In 2008, 525 million gallons of toxic coal ash sludge spilled into the Tennessee River, drawing national attention to the issue of improperly secured waste ponds. The spills continue. In 2011, for example, coal ash broke an impoundment and spilled directly into Lake Michigan from a power plant in Wisconsin. The EPA has identified over 600 coal ash disposal sites across the country. For a map of some of these sites, see here. For a map of disposal sites known to have had leaks, spills, or groundwater contamination problems, see here.
Black lung: a disease on the rise
In addition to pollution resulting from coal combustion and coal ash disposal, coal mining also leads to serious health problems among miners. “Black lung” is the infamous coal miner’s disease, caused by inhaling coal dust, which leads to lung tissue scarring. Technology and prevention strategies have reduced the numbers of miners suffering from this incurable disease in the past four decades. However, recent research points to an increase in rates of the disease, due to miners working longer hours, changes in the composition of rock being mined, and increases in production.
Where is coal burned?
There are 1,400 coal-fired electricity-generating units at more than 600 plants across the country. The Sierra Club maps the location of about 500 coal plants across the country. Coal pollution does not respect state boundaries, however. It can travel hundred of miles, creating acid rain and smog and endangering the health of residents in other states. That is why the EPA is trying to limit the sulfur dioxide and nitrogen oxide pollution from coal plants through the Cross-State Air Pollution Rule. In addition to the hundreds of coal plants currently in operation, there are dozens more in the planning stages. Find out if there’s one planned in your state using this map from the Sierra Club.
What is clean coal?
“Clean coal” refers to technologies in development that could reduce dangerous carbon dioxide emissions by capturing them and storing them either in the earth or in the ocean. Geologic storage involves injecting the captured carbon dioxide a mile or more below the earth’s surface in deep saline reservoirs. Ocean storage involves injecting liquid carbon dioxide hundreds of meters beneath the surface of the ocean, where it theoretically would be absorbed into the water. Both strategies are in the planning and testing phases. Their safety, permanence, efficiency, and resulting ecological impacts are uncertain.