Amid a devastating industry-wide downturn, one of the largest coal producers in the U.S. has filed for bankruptcy. 

Coal-giant Alpha Natural Resources has been in poor financial health for some time. The company acknowledges contributing factors like increased competition from natural gas and an oversupply in the global coal market. But Alpha puts much of the blame for its bankruptcy on environmental regulations that it says are causing electric utilities to shut down coal-fired power plants.

In 2008, Alpha's stock price was more than one hundred dollars a share. Last month, the company was trading as a penny stock and had been delisted from the major exchanges. The news of Alpha’s bankruptcy follows recent bankruptcy filings by many coal companies, although Alpha is by far the largest. It owns mines across the country, including two in the Powder River Basin.

The Virginia-based company filed for Chapter 11 bankruptcy protection on the same day that President Obama unveiled tough new federal rules designed to cut carbon emissions from coal plants and to transition away from the coal that now generates nearly 40% of American electricity.