The watchdog arm of Congress will try to figure out whether the federal government could have prevented the financial crisis engulfing the Central States Pension Fund.

Nearly 300,000 Teamsters could lose a significant chunk of their retirement income under a rescue plan the ­Central States fund wants to pursue.

The nonpartisan Government Accountability Office will review the U.S. Department of Labor's oversight of the fund, the office wrote in a Feb. 12 letter to Sen. Chuck Grassley, R-Iowa. Grassley requested the probe Feb. 1.

"Plan beneficiaries deserve to have a better understanding of what led to the financial failings of Central States and ultimately put their retirement at risk," Grassley said Tuesday.

"Congress needs to have a better understanding of what happened with the Department of Labor's oversight of this pension plan so that any corrective actions, if necessary, can be taken."

The Labor Department has monitored the giant ­Teamsters union retirement fund for more than three decades. Labor obtained a federal court-ordered consent decree ­following its own investigation of gross mismanagement of the fund and self-dealing by fund managers. Grassley said the consent decree gave Labor considerable oversight authority in choosing independent fund managers and changing investment strategies.

Yet the fund slid into crisis under Labor's watch and is now more than $16 billion in the red. To the fury of retirees and workers, the fund is seeking to slash retirement benefits under the controversial Multiemployer Pension Reform Act of 2014.

The cuts would affect 272,600 workers and retirees nationally, including nearly 15,000 in Minnesota.

The financial obligations of the Central States fund are so large that if the fund fails, it would swamp the Pension Benefit Guaranty Corp., the government backstop for private sector pension plans, and result in even larger benefit cuts. The PBGC's multiemployer program is projected to be insolvent by 2024.

The Senate Finance Committee held an informational hearing Tuesday on the challenges to the Central States fund and other multiemployer pension funds, in the midst of political turmoil over the new pension reform law.

Instead of repealing the new pension reform law, Joshua Gotbaum, a former PBGC head now at the Brookings Institution, said Congress should require employers to pay higher premiums for the PBGC.

Trustees of the Central States fund have said they had no choice but to seek painful cuts. The plan is facing insolvency in 10 years, they say, because of trucking deregulation, bankrupt employers exiting the fund, two major recessions and declining union membership.

In mid-February, the trustees sent a letter to every member of Congress saying the Central States fund needs $11 billion to prevent insolvency and meet long-term obligations.

"To Members of Congress who oppose the Central States proposed rescue plan and are encouraging the U.S. Department of Treasury to reject the plan, we ask one fundamental question: What is your alternative to the proposed rescue plan?" Central States head Thomas Nyhan said in a statement last month.

Jennifer Bjorhus • 612-673-4683