Federal workers and retirees who are 62 or older by this Septemb will not be hit by the tough dollar offset President Carter wants to impose on civil servants who become eligible for social security benefits.

Put another way, that means that employes who do not hit their 62nd birthday in time this year would be subject to the "offest" if Congress approves it. The ofthers who would escape the social security offset would be federal workers who become disabled by Oct. 1, or the survivors of empolyes who died before the effective date of the proposed lefislation.

The bill, outlined here Jan. 25, is a long way from becoming law. But the president is serious about cutting social security costs. And Congress -- via the Ways and Means Committee -- will look at various proposals to "deliberalize" the benefits system.

The pension offset proposal is considered so outrageous and unfir by federal and postal workers that many have dismissed its chances of passage. That is dumb. Unfir, it may be, but pretending it cannot happen ignores the political facts of life.

Social security is in serious financial shape. Congress is in the mood to trim its outlays. It would like to find a way to cut future cost grorwth, wich the Carter plan would do.

Carterhs proposal would sharply reduce social security benefits for many eligible federal workers when they retire. Only those persons who hit 62 before the law takes effect, beome disabled or die, would be grandfathered into the present system that permits them to collect dual benefits for whatever they are eligible to collect.

The Carter plan would not affect anyone now drawing a federal pension and social security. It would kick into effect on Oct. 1 of this year, as the bill is now written.

When effective, the president's plan would offest (reduce) social escurity payments to individuals by $1 for every $3 they receive in federal pension that is above the social security payment average.The idea is to prevent retired government workers from "double dipping" (the president's term, not mine) excessively into the social security system. Nobody would loss all social security benefits becuase of a federal pension. But most ex-governmet employes, because they have federal pensions, would lose something.

Who does it hit? Unless you are "grandfathered in" by virtue of age or disability, you would be subject to the offset even if you earned social security credit before or after leaving government service.

Why? President Carter and top aides claim the offset would save millions of dollars from leaving the social security fund and being paid out to federal and postal retirees. At the same time, guarantees in the legislation would protect federal retirees from losing -- through offset -- all earned social security benefits.

Congressional reaction: the House Ways and Means Committee holds the key to all social security-related bills. Chairman A1 Ullman (D-Ore.) is committed to the idea of deliberalizing some aspects of social security to cut costs. Whether he and Rep. J. J. Pickle (D-Tex.) will entertain the social security offset idea this year is unclear. But it is coming up, if not this year then in 1980 or 1981.Pickle is the new chairman of the social security subcommittee.

Is it fair? That is the question a lot of federal and postal workers, and retirees are asking. How can Congress or the president take away benefits they have earned and paid for ? The answer is, it is easy. Congress can do just about anything it wants with social security.

How can it be stopped? Political pressure from federal and postal unions could help stall or kill the offset. Retiree grouos also have a lot of muscle. But it may be that the offset plan would be upset in court, if it ever becomes law. Rep. Gladys N. Spellman (D-Md.) is exploring legal avenues to, perhaps, block it.

Spellman agrees that Congress can do virtually anything with social security, including offsetting benefits if it does the same thing to everbody. That is, offset if you wish Congress: but do it to General Motors and duPont pensions, and to annuities paid residents of Louisiana, and state pensioners of Illinois and California. Not just the feds.

Texas Hat Trick: U.S. Postal Service's Jeanne O'Neill last week became a grandmother three times in one day. Her daughter in Texas had triplets -- all boys.