In the summer of 1956, Sen. Walter F. George (D-Ga.) jammed through the Senate, 47 to 45, a revolutionary new program adding workers to the pensions for disabled workers to the existing Social Security old-age pension system. Under the program, severely disabled workers could start collecting monthly disability pensions at age 50 instead of having to wait for old-age pensions at 65.

Sponsors predicted the costs wouldn't be excessive. By 1980, they said, only about 1 million workers would be on the disability rools and the annual cost would be only about $860 million. Goerge said the cost might not even be that much. He advocated removing the minimum age-50 requirement (a change that has since been made).

Harry. E. Byrd Sr. (D-Va.), one of the few Democrats who joined Republicans in opposing the new program, warned, "I have seen many an aid program start the size of a mouse and rapidly grow to the proportions of an elephant."

Byrd proved more prescient than George. Two years shy of 1980 there are already 4.8 million disabled workers on their dependents on the disability insurance benefits rolls, and the cost has ballooned to about $11.5 billion this year.

In another decade, the rolls are expected to exceed 7 million and the cost will leap to $33.1 billion. The proportion of wormeers on the rolls relative to the working population has mounted steadily.

The rapid startling and unexpected rate of program growth is one of the major reasons why Congress this year has voted massive increases in Social reasons why Congress this year has voted massive increases in Social.

Without huge infusions of payroll taxes, the disability insurance program would have been bankrupt by the end of 1978. The tax rate just to support the disability fund, which started in 1957 at 25 cents a piece for employeers and employees each $100 of a worker's earnings, will be three times that in 1978 and about $1.10 each by 1990. And further increases will be necessary later, since even these boosts don't fully fund the system beyond the next 30 years.

Nobody is quite certain why the program has grown so rapidly, but most observers believe it is getting out of hand. Senate Finance Committee Chairman Russell B. Long (D-La.), an ardent supporter of the George amendment when it passed two decades ago ("This is good sound insurance," he said then), declared in an interview recently, "It's out of control. The program out of control."

Long's committee, the House Ways and Means Committee and the Carter administration are expected to give major attention to finding out how to curb the problem growth next year. They may toughen eligibility requirements of make other changes to block what several officials call "runaway expansion."

Though no one is absolutely sure why the rolls and costs have grown so fast, major factors clearly have been an improvement of benefits and easing of eligibility rules, such as removal of the age-50 requirements. Other reasons often cited are:

Increased public awarness of the program, spurred in part by the government itself.

The rise of a new breed of legal services lawyers and private lawyers who are helping people to obtain benefits, often through appeals to the courts.

High unemployment in recent years, making it harder for disabled persons to get and keep jobs and thus encouraging them to apply for disability and stay on.

The fact that only about 35,000 are rehabilited off the rolls annually.

A presumed "softness" on the part of examiners and appeals officials, who are said to be too lenient to applicants who are old, poorly educated and therefore [WORD ILLEGIBLE] tic chance of getting [WORDS ILLEGIBLE]

The high level [WORDS ILLEGIBLE] able to some workers. [WORDS ILLEGIBLE] ried worker with a child [WORDS ILLEGIBLE] as much as $1,051 a [WORDS ILLEGIBLE] plus Medicare. This is [WORDS ILLEGIBLE] the $690 maximum payment [WORDS ILLEGIBLE] old-age retiree and spouse under the old-age insurance system.

"We've made it so persude themselves they are sick," declared Long. (The average benefit - $517 a month for a disabled worker with a family, $264 for the worker alone - is much lower, much closer to the average $400-a-month old-age couples benefits.)

To be eligible, a worker must suffer "physical or mental impairement . . . of such severity that he is not only unable to do his previous work, but cannot, considering his age, education and work experience, engage in any kind of substantial work which exists in the national economy, regardless of whether such work exists in the immediate area in which he lives, or whether area in which he lvies, or whether a specific job vacancy exists for him or whether he would be hired if he applied for work."

This is a fairly tough definition, and disability benefits are intended for the severly disabled only: the blind, double amputees, persons with cancer, schizophrenia, skeletal disorders like a bad disc in the spine.

In 1975, 30 per cxne of disability insurance had heart or circulatory problems, 19 per cent muscular and skeletal disorders, 11 per cnet mental disorders, 10 per cent neoplasms (cancer), 7 per cent nerve diseases, and so forth.

Over the years the benefit structure has become more generous structure has become more generous, and this accounts - but only in part - for the rise in beneficiaries and costs. In 1958 Congress made the dependents of disabled workers as well as the worker himself, eligible for some monthly benefits. In 1960 it removed the requirement that the worker be at least 50 to receive benefits. Today, workers in their early 20s can get them for the rest of their lives if they have worked in Social Security-taxed jobs for as little as six quarter-years in some cases. Medicare benefits for the disabled person also were added, making it much more worthwhile for a disabled person to seek to get on the rolls.

The typical disabled beneficiary is drawn from the lower economic and educational rungs of society. The median age is 55. Some 68 per cent of the beneficiaries are male. Four-fifths are white, just under a fifth are black - a dispropotionate number of blacks. Three-fifths of the men came from blue-collar work. Two fifths of the white beneficiaries and three-fifths of the black ones never attended high school, and a tiny portion (10 per cent of the whites, 5 per cent of the blacks) have ever attended college.

In 1976 a House subcommittee headed by Rep. James A. Burke (D-Mass.) took an in-depth look at disablity insurance, and particularly at why the monthy maximum payment to a very young disabled worker can be so much higher than that paid old-age retiree.

The reason, explained actuarial consultant John Miller, is that benefits are based on the worker's average taxable monthly wages until he reties or become disabled. An older person retiring today has worked for many years at the lower wages which were prevalent in the economy and subject to Social Security taxes during the early part of his life. But a young worker only a short period, at today's higher general wages and can have a much higher average. Miller calculated that some young disabled workers could actually receive benefits up to 38 per cent higher than their after-tax earnings prior to disability.

This incentive to malingering which Long has alluded to, has been partly corrected. This year's Social Security bill changed the disability computation starting in 1979, so that a worker disabled then with an earnings record similar to one disabled now, could get only $904 a month as a maximum initial benefit instead of the $1,051 that is now available.

One serious problem cited is the difficulty of objectively determining a disabled individyal's work-capacity "considering his age, education and work experience." Witnesses said many examiners and appeals officials have simply been concluding that any severely disabled older person of limited education is unemployable and therefore should be eligible for benefits.

Not everyone agrees that there is substantial malingering encouraged by high benefits, or that tougher disability determinations would force people to get jobs.

"The best test of whether people are malingering is whether they would get jobs if turned down or cut off the rolls," said one officail. "We have studies to show that of those turned down, fully 80 per cent fail to get jobs within five years, suggesting they can't work or are hard to employ."

Dennis Sweeney, chief attorney of the administrative law center of the Legal Aid Bureau of Baltimore, who has handled many disability appeals, said, "I just don't think malingering accounts for a large portion of the growth of the program." He said high unemployment, which makes disabled workers unemployable, more publicity about the program, and more publicity about the program, and more legal aid to applicants are probably the main causes.

Sweeney said some examiners might interpret the law a bit more softly than intended, but to do otherwise would be unrealistic and only force turned-down applicants to apply for welfare.

"When a guy comes in who's worked 30 years in a scrapyard hauling metal on his back - he's 55 with a third-grade education, had two operations on his back for adisc - theoretically perhaps he could perform some nonphysical jobs but realistically [they] know no one will hire him. It's foolish to think he's ever going to get a job."

What these statements suggest is that the rapid growth of the program may not be a correctable aberration but a normal process that society must accept.

Robert Ball, former commissioner of Social Security and one of the authors of the program, said there are signs that its growth may be leveling off and that future costs won't be as high as projected.

For the past two years, the number of claims has dropped for the first time in many years. ball said the program may simply have reached maturity and "projections for rising rolls and costs may prove to be overpessimistic. I'm damned glad to see ti leveling off."

However, congressional experts are not so certain and expect to go ahead in 1978 with a major examination of how to control disability costs. CAPTION: Picture 1, SEN. Walter F. George, He predicted that by 1980 the program would cover only a million workers at a yearly cost of $860 million; Picture 2, SEN. HARRY F. BYRD SR., 'I have seen many an aid program start the size of a mouse and grow to the proportions of an elephant.