Sen. Charles Grassley, R-Iowa, has requested the Government Accountability Office investigate the Department of Labor’s oversight of the Teamsters Central States, Southeast and Southwest Area Pension Plan.

In 1982, the DOL entered into a court enforced consent decree with the Central States fund to assure that it was being managed for the sole benefit of plan participants, as required under the Employee Retirement Income Security Act.

Almost from the point of its inception in 1955, the pension fund was dogged by allegations that assets were routinely loaned to organized crime interests, often to several Las Vegas casinos, and that Jimmy Hoffa, the famed Teamsters boss, received kickbacks from providers to the funds.

In his request that the GAO review DOL’s oversight of the Central States fund throughout the past three decades, Sen. Grassley said he wants to know what actions the DOL has taken regarding the fund’s investment managers and investment strategies.

Specifically, Grassley wants to know if DOL had any influence over how the $6.1 billion lump sum that United Parcel Service paid when it withdrew from the multiemployer plan in 2007 was invested.

“Given the current financial problems facing Central States, and the risk its insolvency poses to the PBGC, the time is ripe for GAO to update Congress on DOL’s oversight of Central States,” Grassley wrote in his request for an investigation.

“It appears that the department hasn’t done enough to prevent a major failure of the fund that could mean a big financial hit for retirees in Iowa, Nebraska and elsewhere around the country,” added Grassley in a statement.

“Central States 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,” said the Senator.

A representative from Sen. Grassley’s office said the GAO has not yet agreed to Grassley’s request.

Last year, the Central States plan was the first to apply to the Treasury Department for the right to reduce retiree pension benefits, a process created by the Multiemployer Pension Reform Act of 2014 for collectively bargained pension funds that are facing impending insolvency.

Once the envy of collectively bargained pension plans, the Central States plan has suffered from dwindling contributions over the past two decades, as employers such as UPS left the plan.

The plan’s funding level was also severely affected by investment losses incurred during the 2008 financial crisis.

But the pension’s troubles are perhaps best explained by the ratio of inactive to active participants in the plan.

According to papers filed with Treasury, actuaries say there are now 5.3 retirees collecting benefits for every one active participant contributing to the pension fund.

In 2015, the pension’s funding status was 47.7 percent, with a market value of assets of $17.8 billion, and more than $35 billion in future obligations to retirees and workers, according to actuaries.

The plan is projected to be insolvent by 2026.