The $1.4 trillion spending bill passed by Congress last week quietly achieves what a parade of select committees and coordinating councils could not: rescue a dying pension fund that is the lifeblood of nearly 100,000 retired coal miners.

For the first time in 45 years of federal pension law, taxpayer dollars will be used to bail out a fund for workers in the private sector. And now that there’s a precedent, it might not be the last.

“We could be the blueprint,” said Chuck Pettit, who mined coal for 42 years. “But we’ve got to do it right.”

The coal miners belong to one of about 1,400 pension plans that cover a large group of workers in a single industry or trade. These so-called multiemployer plans cover more than 10 million workers in unions including the Teamsters, the American Federation of Musicians, the Screen Actors Guild and, in Mr. Pettit’s case, the United Mine Workers of America. Even President Trump has a multiemployer pension, worth about $70,000 a year, earned in his reality-TV days.

But nearly three-quarters of the people with this type of pension are in plans that have less than half the money they need to pay promised benefits, according to the Pension Benefit Guaranty Corporation, the federal agency that insures pension plans. Chronic underfunding, lax government oversight and serial bankruptcies have left them in dire straits. And the guaranty corporation’s program backing up these plans — which operated under the assumption that they were inherently strong — would be wiped out by the failure of just one of the major pension pools.

Unbalanced Sheet

One coal company after another has gone bankrupt and stopped paying into the miners’ pension plan, but the retirees are still there. Its assets are dwindling, but the liabilities have stayed about the same.

“It’s a disaster waiting to happen,” said James P. Naughton, an associate professor at the University of Virginia’s Darden School of Business and an actuary whose clients have included multiemployer pension plans.

The solution approved by Congress uses the Abandoned Mine Lands Reclamation Fund, which is partly supported by a per-ton fee that all coal companies pay. In 1992, Congress allowed the fund to help pay for retired miners’ health care, and the new legislation — the Bipartisan American Miners Act — uses the fund as a vehicle to support the pensions, too. The bill, among other changes, allows the Treasury to send as much as $750 million a year into the fund as it covers the unfunded pension obligations.

How Taxpayers Will Now Help Pay Miners’ Pensions

When the mine workers’ retiree health plan ran out of money in 1989, Congress arranged for new funding sources, including the Abandoned Mine Lands Reclamation Fund and, later, the Treasury. That precedent is now being followed for the miners’ pensions. Starting next year, the Treasury’s transfers to the Abandoned Mine Lands fund will rise to a maximum $750 million a year, and will help pay for pensions as well as retiree health care. This may prompt other unions to seek federal assistance for their plans, too.

A failure to act would have had dire consequences: Tens of thousands of miners, many in already economically distressed areas, would have lost their benefits. And coal pensions support not just families but sometimes whole towns.

Identification cards belonging to Mr. Pettit from his decades as a coal miner.
Credit…Ross Mantle for The New York Times
Mr. Pettit, center, in a decades-old photo signed by Rich Trumka, a former president of the union.
Credit…Ross Mantle for The New York Times

The collapse of the miners’ plan was hastened by the parade of bankruptcies that have hit the industry in recent years. By this fall, just one major employer, Murray Energy, was still paying into the fund. On Oct. 29, Murray declared bankruptcy — the eighth coal producer to do so this year.

Usually, leaving a multiemployer pension plan is an expensive proposition for a company. It must pay off its share of any shortfall to leave. But bankruptcy provides a cheap exit ramp, because the pension plan is treated as an unsecured creditor — the kind that goes to the back when everyone lines up to be paid.

After Alpha Natural Resources declared bankruptcy in 2015, for example, the pension fund’s trustees calculated that it owed $985 million. Alpha got out for about $75 million: a $10 million payment spread over four years and the rest in stock in the new company.

But when companies get out of the pension pool, their employees stay in — and become the responsibility of the companies still kicking in money. As more companies failed, it only increased the pressure on the others to get out.