For the first time ever, older Americans' Social Security checks are subject to garnishment, not by private creditors but by the federal government.

Beginning this month, the Social Security Administration will be deducting payments from checks issued to 55,000 who've defaulted on Veterans Administration mortgages and student loans as well small business and disaster loans. In October it will go after 232,000 who owe money to the Internal Revenue Service.

The unprecedented -- and largely unpublicized -- action is part of an effort to collect $31 billion that individuals owe to various federal agencies. It's the result of an obscure section of the Debt Collection Improvement Act passed by Congress in 1996.

Under rules established by the Treasury Department, the first $750 of an individual's monthly Social Security payment will be off-limits. Fifteen percent of the amount above $750 will be withheld each month until the debt is repaid. Payments to disabled persons and their dependants and survivors under the Supplemental Security Income program are not affected.

Although Congress authorized the garnishments in 1996, the program is just getting underway because of the complexity of linking data from the many different federal departments.

In reality, it will be a while before the program makes much of a dent in that $31 billion. A big chunk of the outstanding bad debt consists of student loans taken out by baby boomers. But putting the program into action now means it should be running smoothly when the boomers begin to retire.

Among today's older debtors are veterans who didn't repay home loans or didn't make required medical co-pays and individuals who didn't repay Medicare overpayments. The average veteran owes $1,000, a VA official said.

Think you might be on the list? The Treasury Department has set up an automated phone number that will tell you. It's 800 304-3107.