COLUMBIA - Gov. Mark Sanford's plan to tweak benefits offered through the state pension system wouldn't do enough to curb mounting debt, according to an analysis by state financial experts.

Sanford proposed last month scrapping the TERI program for future employees and increasing the number of years needed for retirement back to 30 years from 28 years.

But an independent actuarial firm hired by the state concluded Sanford's plan would not head off a looming debt ceiling that threatens to halt cost-of-living adjustments for retirees beginning next year.

In the General Assembly, a growing number of lawmakers say more-radical changes to the state retirement plan are inevitable if it is to deal with its $4.2 billion unfunded liability.

Lawmakers considering changes will face a tough road ahead and risk angering the more than 260,000 state and local workers and retirees enrolled in the plan.

"We plan to fight those changes with everything we have," said Broadus Jamerson, executive director of the S.C. State Employees Association.

Ray Weinstein, a sociology professor at the University of South Carolina at Aiken, said he is opposed to changes in programs such as TERI - the Teacher and Employee Retention Incentive program.

TERI allows state employees to retire, defer their retirement benefits and continue to work up to five more years. Originally devised as a way to retain experienced teachers, it is now open to all state workers.

"The current system is a good deal because it's provided fairly and equitably, and it's one of the few plans that benefits even the lower-level employees," says Weinstein, who has been working for the school since 1976 and plans to take advantage of TERI soon. "It seems as soon as they come up with something good, they can't leave well enough alone."

State Sen. Greg Ryberg, R-Aiken, said the benefits package offered to state employees might be too sweet.

"The problem is, these programs have a huge economic impact that's put on the back of the system," he said. "We can't afford it."

Ryberg said he'll introduce a bill this week that, like Sanford's proposal, would eliminate TERI and return to 30-year retirement.

But Ryberg wants to apply the changes to all employees, not just future ones.

Although that would reduce the plan's debt more than Sanford's proposals, the governor and others say that could open the state to lawsuits from employees who view the benefits as entitlements.

Even so, many lawmakers acknowledge the pension system is boxed into a corner if it wants to give retirees cost-of-living adjustments.

Sen. Hugh Leatherman, R-Florence, said the overall health of the pension plan is good, but he will propose legislation later this year that would revisit how the system's money is invested.

Leatherman, chairman of the Senate Finance Committee, said TERI is not the system's biggest problem.

"I will not be a party to sticking a Band-Aid on it and saying, 'There, we fixed it,'" he said. "We need to look at the entire retirement system and see what we need to do."

South Carolina's pension system's investments are considered conservative compared with those in other state plans. Under state regulations, 40 percent of the plan's investments can be in higher-risk stocks, as opposed to more conservative bonds.