The Pension Benefit Guaranty Corp., in an unprecedented move, yesterday returned to the bankrupt LTV Corp. $2 billion in unfunded pension liabilities contained in three of the company's retirement plans.

The agency, which insures the pensions of 40 million workers, said it was the first time in its 13-year history that it has ordered a company to reassume responsibility for plans that had been terminated because of abuse of the pension insurance system -- a charge the agency is leveling at LTV.

"Companies cannot be allowed to subvert a vital pension protection for millions of Americans to further their own competitive strategies," said Kathleen P. Utgoff, executive director of the PBGC. "Pension promises should not be sacrificed to increase a company's profit or preserve executive bonuses or enhance profit-sharing arrangements."

The PBGC action is an attempt to restore full pension benefits to about 100,000 LTV workers and retirees. LTV, with the approval of the United Steel Workers union and the bankruptcy court, put in place a new pension and benefit system that is less costly for the company and is not federally insured.

The PBGC had terminated the plans last January after it became clear that LTV could not meet its pension obligations. Restoration of the plans is the most extreme of several options the PBGC had been considering.

The three plans returned to the company have more than $1 billion in assets to cover monthly benefits that add up to $30 million. The PBGC will continue as trustee for a separate LTV plan it terminated in September 1986.

"The federal government will not tolerate any interruption in benefit payments to retirees," Utgoff said. "If there is any hesitation on the part of the company, we'll take any of the necessary legal steps available."

LTV said it will challenge the PBGC in federal court, and that retirees should expect to continue receiving their current benefits -- not those mandated by the PBGC.

"We will immediately initiate steps to make interim payments to retirees at current levels," said Raymond A. Hay, chairman and chief executive officer of LTV Corp., who said the PBGC move is illegal.

Utgoff said the agency has the authority to give the plans back to LTV under the Employe Retirement Income Security Act.

"LTV can afford to fund its pensions now and there is no reason why retirees shouldn't be receiving full benefits," said Utgoff, referring to $252 million in LTV operating profits for the first six months of the year and other major expenditures that have been approved by the bankruptcy court.

The agency said the "follow-on" plans that the company has devised since the termination of its old plans are illegal since they essentially duplicate the obligations that were abandoned by the company but are now footed by the PBGC.

The agency also said that money the company is saving on reduced pension obligations subsidizes other benefits such as profit sharing at the expense of retirees.

Utgoff said the action should "send a message to other steel companies that we won't have the program used to {let them} get a leg up on the competition at the expense of retirees."

Including the LTV claims, about 80 percent of the PBGC's obligations are steel related. Since the bankruptcies of LTV and, earlier, Wheeling-Pittsburgh Steel Corp., the agency has feared its $4 billion deficit would balloon further if more steel companies regarded bankruptcy as a competitive strategy.

LTV maintained that despite operating profits it faces $6.5 billion of debt and that it continues to be in no position to fund the original plans.

"The company did not in January and does not in September have the resources to fund the plans in accordance with ERISA," Hay said. "The PBGC action not only weakens the plans, but makes active workers and retirees pawns in an unnecessary game."

Pension experts expect that if the company is forced to meet its original obligations it will seek waivers from the Internal Revenue Service to avoid immediately making the payments.

Whatever legal skirmishing goes on between the agency and the company will not affect the monthly benefits paid to retirees covered under the plan for hourly workers for Republic Steel Corp. and the plans for salaried and hourly workers for Jones and Laughlin Steel Co. -- the retirees affected by the PBGC restoration.

Both of those companies, and their pension obligations, were acquired by LTV.

But Sen. John Heinz (R-Pa.) said he feared that the dispute has turned into a "Ping-Pong match between the PBGC and the company. Unfortunately the ball is the financial security of the steel retirees."

Rep. J.J. Pickle (D-Tex.), who is working on pension reform legislation, called the PBGC move a "proper" one. "Employers who make pension promises should be held fully responsible for funding those promises.