CHEYENNE, Wyo. (AP) — Turns out the worst state for carbon dioxide emissions per person isn’t smoggy California or bustling New York, but a place famous for its big, clear skies: Wyoming.

But regulating greenhouse gases is a touchy subject in the least-populated state, which just recently received U.S. Environmental Protection Agency approval to do so.

Wyoming also is the top coal-mining state by far, producing almost 40 percent of the nation’s coal. Burning coal to generate electricity produces large amounts of CO2 — in Wyoming, across the U.S., and in the Far Eastern countries where state officials have sought to open up new coal markets.

Gov. Matt Mead made such a trip to Taiwan and South Korea last year. Meanwhile, he’s called EPA efforts to curtail greenhouse emissions a “war on coal” and said at a recent forum he’s skeptical about man-made climate change.

“What he also says is we do have a responsibility to always do things better,” Mead spokesman Renny MacKay said Thursday. “The coal industry has to be profitable if it’s going to invest in the research and development of new technologies.”

MacKay highlighted the state’s efforts to make its coal cleaner: $50 million allocated toward new coal-burning technology at the University of Wyoming and plans by the state to support a proposed $10 million X Prize to develop economically feasible carbon-capture technology at an operational coal-fired power plant.

He said the EPA shouldn’t impose rules that cripple coal-fired electricity by requiring still-unattainable greenhouse reductions, but, instead, should gradually implement rules as new technologies to cut carbon emissions become available.

The stakes for Wyoming are high. Minerals taxes on coal provided $1 billion to the state and local governments in 2012 and coal mining supports some 6,900 jobs in the state.

Last year, Wyoming’s coal production fell 3 percent amid more stringent environmental regulations and inexpensive natural gas, a cleaner fuel source in growing use by electric utilities. Meanwhile, per person, Wyoming faces an outsized challenge to regulate greenhouse gases on a shorter timeframe than breakthrough technologies are likely to allow.

Burning coal — nearly all of it to make electricity — accounted for 69.2 percent of Wyoming’s CO2 emissions, twice the U.S. average.

Only West Virginia (80.9 percent) and North Dakota (69.4 percent) had more of their CO2 emissions come from coal.

Wyoming residents aren’t solely responsible for all of those emissions. Wyoming exports to other states about 68 percent more electricity than it consumes in state.

“Certainly other states, to put it mildly, they have blood on their hands as well,” Jeremy Nichols of WildEarth Guardians said Thursday.

The group has two active lawsuits opposing coal mining in Wyoming on climate-change grounds.

In December, Wyoming became one of the last several states to get EPA approval to regulate greenhouse gases. For over a year and a half, the EPA regulated greenhouse emissions in Wyoming while the state regulated other types of air emissions, a “dual permitting” process that resulted from a 1999 state law that said Wyoming wouldn’t enact any regulation reducing greenhouse gases.

The Legislature repealed the law over the last two years.

State regulators say they’re still waiting to see many details of how the EPA intends to regulate greenhouse emissions, including possible new rules for existing power plants, said Steve Dietrich, head of the Wyoming Department of Environmental Quality’s Air Quality Division.

Other states with high per-capita CO2 emissions included North Dakota, at about 78 metric tons per person, followed by Alaska (53) and West Virginia (52).

Vermont, California and Connecticut had the fewest emissions per person, all with just above 9 metric tons per capita.