While Trump campaigned on a promise to revive the coal industry, the sector has declined during his presidency. Although the president has rolled back 85 environmental rules in an attempt to help revive business, according to The New York Times, a natural gas boom and the country’s increasing use of renewable energy sources have stymied those attempts. Coal provided just 27.5 percent of Americans’ electricity last year, according to the Energy Information Administration, down from nearly half just a decade ago.

The natural gas boom and the increasing capacity of renewable energy have contributed to coal’s decline, a trend marked by a string of bankruptcies. Armstrong Energy Inc and Mississippi Minerals filed for bankruptcy in 2017. Mission Coal and Westmoreland Coal filed for bankruptcy in 2018. Trinity Coal filed for bankruptcy in March and was followed by Piney Woods Resources Inc in April, Cloud Peak Energy in May, Cambrian Holding in June, and Blackjewel and Blackhawk Mining in July. Murray, Cloud Peak and Revelation Energy/Blackjewel were among the nation’s top 10 producers in 2018, according to the EIA.

Murray Energy, the largest privately-owned coal company that employed almost 5,550 people in 2018 is the latest casualty. The company owned and operated 13 mines across the county and managed five additional mines, but had accumulated about $2.7 billion in debt, the bankruptcy filing said. The company also has more than $8 billion in actual or potential liability.

For environmental advocates, the filing represented progress toward a cleaner future.

“Bob Murray and his company are the latest examples of how market forces have sealed the fate of coal and there’s nothing the president can do about it,” Ken Cook, the president of the Environmental Working Group, said in a news release.

But the bankruptcy filing generated concerns from the United Mine Workers of America, which said sounded an alarm about its ripple effects on workers through the country.

“Now comes the part where workers and their families pay the price for corporate decision-making and governmental actions. Murray will file a motion in bankruptcy court to throw out its collective bargaining agreement with the union. It will seek to be relieved of its obligations to retirees, their dependents and widows. We have seen this sad act too many times before,” the organization said. “But that does not mean we will sit idly by and let the company and the court dictate what happens to our members and our retirees. We have high-powered legal, financial and communications teams in place that will fight to protect our members’ interests in the bankruptcy court.”

West Virginia Senator Joe Manchin also signaled concern and introduced the “Stop Looting American Pensions (SLAP) Act” on Tuesday.

“If Murray Energy refuses to pay their pension obligations, the UMWA pension fund will be insolvent by this time next year. The SLAP Act ensures all workers, union and non-union, are treated fairly when a company files for bankruptcy and ends the inequities of the current system,” Manchin said in a statement.

Update, 10/30, 4:04 p.m.: This article has been updated with more detailed data and the headline has been changed to reflect the alteration. S&P Global Market Intelligence found that 11 companies have filed for bankruptcy since Trump took office. Using information provided by the Institute for Energy Economics and Financial Analysis, an initial version of this article said that eight companies had filed for bankruptcy since Trump took office.