WASHINGTON -- More than 33 million workers qualify to have their student loans forgiven because they work in schools, hospitals or city halls, but too few take advantage of the options because the programs are overly complicated and often confusing, the government's consumer advocate said Wednesday.

Roughly a quarter of the U.S. workforce could take advantage of federal rules that give favorable loan repayment options to those in public service fields, including the military, according to the Consumer Financial Protection Bureau. The agency recommended Congress review the loan forgiveness programs and encouraged employers to make sure their workers know they are available.

"Teachers, soldiers, firefighters, policeman -- public sector careers invariably involve some effort, some inconvenience or some sacrifice. People give up higher incomes to serve their city, their state or their country," said Richard Cordray, director of the CFPB. "We believe that people who contribute part of their talents, part of the benefits of their education, to society as a whole should not be mired in debt because they stir themselves to the calling of public service."

Student loan debt has topped $1 trillion, the consumer advocate estimates, and has been a drag on the economy as graduates are forced to choose between paying down their loans and buying a house or a car.

For many graduates, there are multiple programs in place to ease the financial burden of taking lower-paying jobs to help their communities. But the system is fraught with complications and competing options and a firm number of how many graduates could benefit is hard to come by.

"The data is quite weak in this area. We don't have a sense of how much money is left on the table," said Rohit Chopra, the CFPB's student loan ombudsman. "But we suspect it's a substantial sum."

The consumer advocacy bureau knows how many people qualify because they work under the broad umbrella of public service.

"We estimate that one in four working Americans has a job that meets the definition of public service under this program. Many of these teachers, health care workers and other public servants could be eligible to have their college loans wiped out after ten years," Cordray said. The definition is broader than that, though. For instance, clerks at the state department of motor vehicles office, secretaries at city hall and accountants at non-profit arts groups also qualify for the loan forgiveness programs -- positions not typically seen as public service jobs.

But the largest group of beneficiaries would be those in education -- more than 6.8 million people.

"Public service employees -- most especially teachers -- never get into the teaching profession to get rich. They have a deep passion," said Jeffrey Bourne, the chairman of Virginia's Richmond School Board.But it's tough to recruit teachers, he said, and loan forgiveness programs make it easier for new teachers to take lower starting salaries than their classmates as they start their careers.