In a Baltimore working-class neighborhood, retired steelworker Antonio (Tony) Pierorazio opens his mail to find that his usual monthly pension payment from the financially troubled Eastern Stainless Steel Co. has been slashed nearly in half, from $1,239 to $632. "It was negotiated to be there, so when it isn't there, it is like someone stealing from you," he said, "and that is hard to take."

In the rolling hill country of Cumberland, Md., former textile worker John Estes joins with other retirees to protest the Celanese Corp.'s diversion of the multimillion-dollar surplus that had piled up in the company pension fund. "They grabbed the biggest part of our pension fund . . . after handing us brochures and pamphlets for years that said the money was going into a fund for retirees," Estes complained bitterly.

And, in downtown Washington, Kathryn Foxhall contends that the American Public Health Association, where she works as the editor of the monthly newspaper, did away with the employe pension plan and replaced it with a less secure program. "The problem is that the new plan is not insured," she said.

Foxhall, Estes and Pierorazio are among the growing number of American workers and retirees who feel threatened by and outraged at what they believe to be the failure of the private retirement system to live up to its promises and to deal with them fairly.

Behind this reaction, according to experts familiar with the system, are increases in the number of troubled pension plans, although most pension plans are healthy and most employes get what they are promised, according to federal regulators.

But more than 2 million active and retired workers have been touched by what pension experts describe as a developing pension fund crisis. Thousands of workers have suffered because their pension plans had too little money; perversely, thousands more have been threatened because their pension plans have earned too much money, the experts say.

Pension Benefit Guaranty Corp., a federal agency funded with employer contributions, has been forced to pick up so many underfunded pension plans that the agency is running a $4 billion deficit. Congress is moving to amend the 1974 landmark law known as the Employee Retirement Income Security Act and rescue the ailing agency, which has $3 billion in assets to pay $7 billion in pension obligations. Nearly four-fifths of the $4 billion deficit is attributed to steel industry claims, including LTV Corp., the nation's second-largest steel producer, which filed for bankruptcy reorganization.

"It is inexcusable that we allow companies to escape into Chapter 11 bankruptcy today, to dump their retirees at the bankruptcy door, and to emerge profitable later with no further obligation to them," said Sen. John Heinz (R-Pa.), who is among those who advocate changes in pension law.

What comes out of current efforts to overhaul the $2 trillion pension system will have far-reaching social and economic implications for everyone, according to Nancy Altman, a pension specialist who teaches at Harvard University Law School.

"We have an aging population," Altman said, "and this issue involves not only matters of security and whether the elderly will be able to retire and maintain their standard of living in the future, but also equity among workers."

More than 355,000 workers have seen their benefits jeopardized because they belong to the 1,345 plans that have been terminated since 1974 because financially troubled employers went bankrupt or were unable to meet pension obligations.

Retirees from those companies still get pensions, because the plans were insured through the Pension Benefit Guaranty Corp. But 10 to 15 percent of the retirees get reduced pensions as a result of the agency's limits. It will not pay benefits exceeding $1,857.95 a month, and it reduces benefits for early retirees and for thousands who have received special pension supplements.

A larger number -- an estimated 1.6 million workers -- are confronted with a different problem. They belong to the 1,406 pension plans with an excess of funds. These plans accumulated huge surpluses because of high interest rates and massive stock market increases in the late 1970s and early 1980s. Corporations, to capture those extra funds legally, have been terminating the pension plans, keeping the surplus, and setting up new plans that are often less generous.

Since 1980, when the surpluses made the pension funds attractive enough to seize, companies have voluntarily terminated plans containing $35 billion. After calculating that they would need $19 billion to satisfy their pension obligations, the companies captured $16 billion in surpluses.

"Pensions are like corporate cookie jars," said Pension Benefit Guaranty Corp. executive director Kathleen Utgoff.

These corporate takeovers of pension surpluses have led to a heated and still unresolved dispute between workers and companies -- with each side claiming the surplus as its own.

Congress is considering legislation to govern these takeovers, as part of a broader look at pension reform. Congress is also under pressure to shore up the Pension Benefit Guaranty Corp. by raising the rates employers pay to insure their pension funds. Furthermore, lawmakers are considering various proposals to improve the voluntary private pension system without overburdening corporations.

At Eastern Stainless Steel in Baltimore, where Pierorazio worked, the pension plan established for union workers has a $27 million gap. That is the difference between the fund's $12 million in assets and its $39 million pension obligation to the plan's 1,072 participants, including 383 retirees.

The plan is underfunded because Eastern failed to make annual contributions and because it agreed to steelworkers union proposals for "rich pension benefits," according to William F. Dausch, vice chairman of Eastern's parent company, Eastmet. "Back in the heyday, before imports became a big problem and when business was profitable, nobody suspected this would lead to underfunding," Dausch said.

Pierorazio, 49, went to work at Eastern at age 18 and remained there 30 years, volunteering for every overtime assignment to build up the salary base on which his retirement would be calculated.

"I worked many conditions -- dirty, dusty, filthy, oily, hot and cold," Pierorazio said. "I worked inside the furnaces where your shoes can catch on fire, because you can only stay 10 minutes. I worked in the slag pits. I did not refuse any job, because I knew I was building my pension."

But in recent years, as signs of Eastern's financial problems surfaced, Pierorazio decided to retire and take his pension rather than risk a layoff. "I knew by the grapevine that they were going to do without us if they could, so I left to save my pension," he said.

Pierorazio also left with the idea of trying to parlay his savings and retirement check into a small business. In July 1986, two months after retiring, he bought a franchise for a french fried potato business, Boardwalk Fries, in the East Point Mall in Baltimore. Less than six months later, Eastern cut pensions for 35 to 40 retirees.

Pierorazio's pension was reduced from $1,239 to $632 a month. The size of the cut was governed by federal rules for companies seeking to turn over underfunded pension plans to Pension Benefit Guaranty Corp.

Because of his age, Pierorazio is eligible for only half the usual pension.

"It's a mental strain," Pierorazio said. "First of all, you become irritated, edgy, when you know this should never have been done . . . . Thank God I have my health. That keeps me going."

Pierorazio and other Eastern retirees have hired Washington lawyers Peter Shinevar and Hope O'Keeffe to oppose the Pension Benefit Guaranty Corp. takeover of Eastern's pension fund. They argue that the company, now in bankruptcy court, should be required to stand by the commitment to its workers.

Dausch said that the company cannot raise the money needed to meet its pension obligation.

He said that if Pension Benefit Guaranty Corp. refuses to take over pension payments, the Eastern fund eventually will run out of money and there will be no pensions for retirees.

Pension Benefit Guaranty Corp., which has never denied a company's request for a distress termination of its pension plan, is expected to decide on Eastern's application this summer.

While underfunding is responsible for Pierorazio's predicament, overfunding has aroused John Estes and several hundred other Celanese retirees. They have formed a group called Celanese Retirees Asking Fair Treatment.

The dispute dates to Jan. 23, 1984, when Celanese won Pension Benefit Guaranty Corp. approval to terminate the company's pension plan. At that time, the pension fund, bloated from investment earnings, contained $430.8 million.

Celanese calculated that only $105 million was needed to meet its promises to 7,292 active and retired workers, according to records.

That left a surplus of $326 million, Pension Benefit Guaranty Corp. records show, which Celanese diverted to other corporate purposes.

The recapture of the surplus was disclosed by Celanese in a 1983 news release headlined "Celanese Improves and Restructures Retirement Plan." The four-paragraph announcement said that the company was planning "a number of major improvements to the Celanese Retirement Income Plan" and that the company would receive approximately $160 million after taxes.

After terminating the pension plan, Celanese bought individual annuities from an insurance company to guarantee benefits for retirees.

But the retirees contend they will lose substantial benefits because the surplus will not be used to upgrade pensions and provide future cost-of-living improvements.

Estes, a scrappy 77-year-old, said: "They snatched our money." Celanese Retirees Asking Fair Treatment has hired Washington lawyer Michael S. Gordon to determine if the retirees can recoup any of the surplus.

After working 43 years at the Celanese textile mill in Cumberland, Estes retired in 1973. He and his wife Dessie live in a small house near the now-shuttered mill, and he receives a monthly pension of $261.

"We don't eat and drink off the top shelf," he said, "and we have had to learn to live within our means."

In the late 1960s, when Celanese introduced its pension plan, Estes said, the company presented workers with a pamphlet titled "Paying for Your Pension: When and How It's Done."

The pamphlet contained cartoon panels featuring a worker named Bob Ferguson, who asks questions about the pension, and a manager named Walter Miller, who answers. Among other things, Bob asks what would happen if the pension plan were ended for some reason.

"The chance of that happening is very remote," Miller replies, and he concludes by saying that " . . . in any case, the company couldn't get back any of the money."

"They misled us," Estes said.

Officials at Celanese, now merged with American Hoechst Corp., said they are not familiar with that pamphlet.

"This is a different company now," said spokesman Edward C. Norton, "and I doubt that even the people who were in the old Celanese Corp. would remember back that far."

Norton denied that retirees lose cost-of-living increases under the new plan. He noted, for instance, that the company increased pensions by 4 to 8 percent in 1985 for eligible retirees.

He declined to comment on retirees' assertions that the company misled them and that the surplus belongs to them, saying, "It's something to iron out in court."

Kathryn Foxhall, 37, worries about another aspect of pension plan termination.

At the American Public Health Association, where she has worked for 12 years, management terminated its traditional pension plan, which provided her and other employes with specific retirement benefits that were to be paid by the association. Under that "defined benefit" plan, Foxhall's pension upon retirement would have been 60 percent of the salary she earned at that time, minus two-thirds of her Social Security benefits.

But the promises of that plan ended July 1, 1983, when it was terminated. The association distributed $450,000 from the fund to satisfy pension obligations to 80 plan participants. That left the association with a surplus of $752,000.

Under the new plan, a tax-deferred annuity, Foxhall's pension no longer has a specific, defined benefit. Instead, the size of her retirement benefits depends on her contributions to the annuity and the investment performance of that annuity.

"It could pay more and it could pay less," Foxhall said. "The point is, we don't know what it will pay."

Contributions to the annuity are provided by the health association and the worker, with the association contributing an amount equivalent to 5 percent of a worker's salary a year and matching up to 5 percent of the annual contributions made by the worker.

She said this puts some employes in the risky position of perhaps losing much of their retirement benefits if they are unable to make the contributions necessary to build up their retirement annuity, or if the investment they select gets wiped out in the market.

The association's deputy executive director, Paul Hall, said that Foxhall is "flat wrong" in saying the new plan lacks security.

Hall said that an employe can lose benefits under the new plan by choosing an investment dependent on stock market performance.

But the employe can avoid that risk, he said, by choosing a more conservative investment guaranteed by an insurance company.

"Obviously," Hall said, "if the insurance companies go belly up, the guarantees are not great."