Illinois coal exports have risen sharply in recent years, even as its high sulfur content limits its demand in the U.S.
The state Department of Commerce and Economic Opportunity says that about 12 million tons of Illinois coal was exported in 2013. That's down from the 13 million tons exported in 2012, but far more than the 5.5 million tons exported in 2011 and 2.5 million tons in 2010.
Other coal-producing states are seeing similarly strong exports as the U.S. reduces its reliance on coal-burning power plants.
But critics say exports are shifting pollution to other countries, some with more lax environmental standards. They say that makes the U.S. appear to be making more progress than it is on global warming.
Illinois coal production accounts for about 4,000 jobs.