Health insurance premiums for many federal workers and retired employees could double next year. A big, big hike is certain if Congress goes with a Senate Finance Committee plan that would require the government's employee health insurance program to take care of most hospital and doctor bills of retirees now paid by Medicare.

The proposal, cleared 17 to 2 by the Senate unit, would make the Federal Employees Health Benefits (FEHB) program the primary payer of health and hospital costs for all federal and postal retirees. Currently retirees eligible for Social Security have the bulk of their medical bills paid for by Medicare when they reach age 65. The civil service program picks up lesser amounts and Medicare deductibles.

The civil service program already is the primary payer for retirees not eligible for Social Security.

There are 10.5 million workers, family members and retirees in the government's in-house health insurance program. There are many plans, but half of the group is covered by Blue Cross-Blue Shield. The typical rate for an employee with high-option, family coverage under that plan, for example, is $30.52 per pay period (every two weeks). The government pays $35.65 for that plan. Premiums for employees could go up 80 percent to 100 percent in some plans if the change is made.

Over half of all federal retirees, because of work outside the government or because of a spouse, are eligible for Medicare at age 65. They pay less than $12 a month for Medicare which then becomes the primary payer of most of their medical bills. Some items not covered by Medicare are paid by the FEHB.

The Senate Finance Committee action would reverse that. It would require FEHB to be the primary payer. Officials say this would cause dramatic premium increases -- for both active duty and retired federal workers -- with the amount of the rise depending on the number of retirees enrolled in a given plan.

The Finance panel's plan still has to move through the Senate and has yet to move out of a House Ways & Means subcommittee, but its prospects are good enough to give federal union leaders the willies.

If the changeover occurs, federal officials, union leaders and administrators of some insurance programs say it could wreck the FEHB program, with hundreds of thousands of workers and retirees shifting plans annually to escape higher rates. "We see two things occurring in the federal program is this change is made," and one U.S. official who asked not to be identified: "The change would either produce a near-disaster for the program or a total disaster; we don't see any middle ground."