The House passed and sent to the Senate yesterday legislation that would drastically reduce the "offset" that has cut the Social Security spousal benefit of thousands of male government retirees and which is now being applied to women retiring from federal service.

Under the House plan, the dollar-for-dollar offset against the Social Security benefit that a government retiree gets based on Social Security earned by his or her spouse would be changed so that only one-third of the federal pension would be considered for offset purposes.

Currently, for example, a federal retiree with a $400 monthly U.S. pension who is eligible for a Social Security spousal benefit of $250 a month has all of that spousal benefit eliminated by the dollar-for-dollar offset.

Consequently, such a retiree gets none of the $250 in Social Security spousal benefits.

Under the House provision, the same person used in the example above would be allowed to get a Social Security spousal benefit of $118. This is figured by calculating the offset amount (33 percent of $400, which equals $132), then subtracting that amount from the $250 spousal benefit.

For the past five years, the spousal Social Security benefit of male federal retirees has been reduced dollar for dollar by the amount of the government pension they earned.

Offset did not apply to women until this Dec. 1. Women who were eligible to retire from their government jobs by that date will continue to be exempt from any offset of a spousal Social Security benefit.

They do not have to be retired by Dec. 1, but merely eligible to retire by then.

Those women not eligible to retire until after Dec. 1 are now subject to the same offset rule that has applied to men.

Those women and all men would come under the one-third offset rule if the House change is approved by the Senate and the president. However, there would be no back payments for amounts "lost" in the past to the dollar-for-dollar offset.

A spokesman for the National Treasury Employees Union, which has been lobbying hard to get Congress to reduce the offset formula, said there is a good chance that the provision -- a legislative rider to a tax bill relating to the U.S. Virgin Islands -- will clear the Senate.

The tax bill -- one of those noncontroversial measures that lend themselves to riders such as this -- has already been cleared once by the House and once by the Senate.

But each has added provisions to the bill, and the measure must now go back to the Senate for approval, or to a joint Senate-House conference to iron out differences.