Catastrophic health insurance protection under Medicare would be optional for federal and postal retirees under a proposal Blue Cross-Blue Shield will make today to the House Employee Benefits Subcommittee. The Blue Cross-Blue Shield plan would add a separate Part C category for Medicare that would provide catastrophic health coverage. Medicare now has Part A, which covers hospital, and Part B, which provides insurance for doctors' bills.

Under legislation already approved by the House, many federal retirees who are 65 and older would be required to pay extra premiums of $500 per year or more for catastrophic coverage under Medicare even though many have comparable or better coverage under their federal health insurance plans. Because premiums for the new coverage under Medicare would be based on an individual's taxable income, individuals whose primary income comes from non-taxed Social Security benefits would get the coverage at lower cost than federal and private sector retirees who get most of their income from taxable pension benefits.

The Senate is scheduled to act this week on its version of a catastrophic health protection bill. Whereas the House plan makes coverage -- and the higher premiums -- mandatory, the Senate proposal would allow federal workers to opt out of the catastrophic coverage under Medicare if they also dropped out of Part B of Medicare, which covers bills for doctors and other services.

Blue Cross-Blue Shield delivered its proposal yesterday to Sen. David H. Pryor (D-Ark.), who is seeking a compromise to provide premium relief for federal and private sector retirees, and to Rep. Gary L. Ackerman (D-N.Y.), who begins House hearings today on the impact of the double coverage and double premiums on certain retirees. Under the Blue Cross- Blue Shield plan all premiums for Medicare Part B would be raised about $4 per month to help pay for the added cost of the new catastrophic protection plan.

Federal retiree groups and unions oppose the mandatory double-coverage and double-premium plan cleared by the House. But the Blue Cross- Blue Shield proposal is unlikely to fly unless organizations can convince the House Ways and Means Committee that it is feasible and would not result in unfinanced added costs to the Medicare program.Job Mart

The U.S. Park Police are looking for a few good men and women. Private police jobs start at $20,556. Call 487-9790.

The Coast Guard wants a GM (merit pay) 14 supervisory procurement analyst. Call 267-2331.

Federal Energy Regulatory Commission needs a labor relations specialist, GS 12/13, and a personnel assistant, GS 5/6/7. Call 357-5669.

The Army in Warrenton, Va., has openings for two contract specialists, GS 9/11. Call Nancy Dove at (703) 347-6203. Job Hunters

First Class Inc. is offering a special two-hour course in preparing a Form 171, Uncle Sam's standard job application. The Nov. 11 session is at 1522 Connecticut Ave. NW, and is taught by Housing and Urban Development's Terry Smith. Call 797-5102. The Association of Part-Time Professionals will have a seminar on part-time work opportunities at 6 p.m. Oct. 15 at the Tysons Westpark Hotel. Call 734-7975.