Social Security (search) disability benefits may not be safe from the across-the-board cuts that are likely in President Bush's proposal to allow personal investment accounts.

Retirement and disability benefits (search) are calculated using the same formula, so if future promised retirement benefits are cut, then disability benefits also would be reduced -- unless the program is somehow separated.

That also raises big questions about how investment accounts would be structured for disabled people, especially if they get injured at a young age or are dependent on a parent. Disabled beneficiaries typically work less and need benefits sooner, so the accounts would not provide enough income to these people.

"The Social Security programs are insurance programs, not investment programs, designed to reduce risk from certain life events," said Marty Ford of the Consortium for Citizens With Disabilities (search).

Currently, disabled workers move seamlessly through the Social Security system, often unaware they draw their benefits from the disability program until they reach retirement age and shift to the retirement program. That would change with investment accounts, advocates claim, with people falling through holes in a new system.

About 16 percent of the 47 million people receiving Social Security benefits are disabled workers and their dependents. The impact of accounts on beneficiaries who aren't retirees hasn't been publicly discussed yet by the Bush administration.

Supporters of Bush's overhaul say that disability should be treated as a separate program.

"The proper way to deal with this is to essentially make it clear that these are two different programs and to separate the benefit formulas," said David John, Social Security senior analyst at the Heritage Foundation.

"One is an insurance program and one is essentially a retirement program," John said. "They have vastly different characteristics, they have vastly different administrative structures."

But disability advocates argue that the two programs can't be easily separated. Bush wants to let younger workers invest much of their 6.2 percent in payroll taxes into personal investment accounts (search), similar to a 401(k). Of the tax, 0.9 percentage point funds disability benefits, while the remainder is for retirement benefits.

Almost three in 10 of today's 20-year-olds will become disabled before reaching age 67, according to the Social Security Administration (search). About 72 percent of the private sector work force has no long-term disability insurance.

Advocates worry that some of the nation's most vulnerable and needy people will be hurt by Bush's plan to remake Social Security.

"Anything they do to the retiree formula will affect people with disabilities," Ford said.

That's what occurs in the main plan offered by Bush's 2001 Social Security Commission (search) charged with crafting a proposal for investment accounts. Promised disability benefits get reduced along with retiree benefits, in some cases up to 46 percent. The cuts were used to make the plan's finances add up in the report.

The commission plan is serving as a blueprint for legislation the Bush administration would like Congress to consider. Bush's commission did not recommend changes for the disability program and cautioned that the benefit reductions shouldn't be viewed as a suggestion.

But, "in the absence of fully developed proposals, the calculations carried out for the commission and included in this report assume that defined benefits will be changed in similar ways for the two programs," the commission said.

The commission noted that disabled beneficiaries may not have their full adult lives to accumulate enough funds in their accounts, a rationale for maintaining their traditional benefits.

But if future retirement benefits are cut and disability benefits were maintained at levels being promised under current law, that would encourage an increase in disability applicants, and potentially, fraud, the commission said.

John said separating the programs, but continuing to coordinate benefits as disabled beneficiaries move into retirement is not an "insurmountable objective." Investment accounts also could be used to supplement benefits for some of the more difficult cases, he said. If a 32-year-old worker becomes disabled, the account could continue to earn interest until he reached retirement age at 67, and help supplement retirement benefits.

Some proposals bar workers from withdrawing money if they become disabled, when money probably is needed most, said Peter Orszag, an economist at the Brookings Institution and former Clinton White House adviser.

"There is just an underlying tension between the kind of social insurance features of Social Security and individual accounts," Orszag said. "There are all sorts of beneficiaries where the account model just doesn't really work that well."