A labor-backed group is objecting to a U.S. Education Department proposal to expand federal funding for public charter schools, after the agency’s inspector general issued a scathing report that found deficiencies in how the department handled federal grants to charter schools between 2008 and 2011.

The inspector general discovered some charter schools received federal dollars but never opened their doors to students, and the agency could not say where the money went.

The department has given $1.7 billion in grants to charter schools since fiscal 2009, according to an agency spokeswoman. In its budget request for 2016, the Obama administration is seeking $375 million for the program — a 48 percent increase over current funding levels.

Public charter schools are funded by tax dollars but managed privately and often are not unionized. Education Secretary Arne Duncan has been a strong advocate for charter schools, a position that puts him at odds with teachers unions.

The Alliance to Reclaim Our Schools, which includes the National Education Association, the American Federation of Teachers and the Service Employees International Union, wrote to Duncan on Monday, asking how his agency could seek to expand the charter schools program “despite mounting evidence of significant fraud, waste and abuse within the charter sector, and despite the warnings of your own office of inspector general that federal charter start-up and expansion funds are not adequately monitored or accounted for.”

The inspector general found that the department had been lax in making sure federal dollars were spent in accordance with the law and failed to follow up when others flagged problems.For example, state officials in Florida found “serious deficiencies” in 2008, but it took the federal agency 29 months to react. And when it did, it deemed the Florida problems “resolved,” but the inspector general later found those same problems persisted.

Federal dollars find their way to charter schools through two routes. In most cases, the federal government awards money to a state, and the state hands out grants to charter schools. In some instances, the federal government directly awards money to a public charter school.

But the inspector general found lax oversight in both categories of charter school grants, with the federal agency failing to review the fiscal activities of charter schools that received federal dollars. In addition, the staff at the department in charge of the charter schools program didn’t have adequate training in fiscal and program monitoring, the audit found.

“There is a heightened risk that grantees were not fully complying with program goals and objectives as well as federal laws and regulations,” the inspector general found. “As a result, there is increased risk that department funds were not used for the intent and purpose of the program.”

The alliance is seeking a moratorium on new federal funding for public charter schools. Its letter to Duncan asks what specific actions the department has taken since 2012 to step up monitoring and accountability regarding charter school grants.

Nadya Dabby, an assistant deputy secretary, said her agency has completed 14 of 17 corrective actions outlined by the inspector general and has added staff to the charter program to improve monitoring.

Still, the federal role is largely focused on funding and not direct oversight of the grants, Dabby said. “It’s the responsibility of states to make sure they develop and submit plans for subgrantee monitoring,” she said.

The inspector general looked at three states — Arizona, California and Florida — and found multiple weaknesses in the ways those states oversaw federal dollars sent to charter schools.

California state officials were “unqualified to conduct onsite monitoring of charter schools,” the inspector general found. Of 13 state employees responsible for visiting charter schools, seven did not have the necessary experience and the state could not provide qualifications for two more, the audit said. Some of those state employees told the inspector general’s staff that they felt “awkward” conducting site visits because they didn’t know much about charters and fiscal matters.

In the three states that were audited, the inspector general found that 26 charter schools either closed during the audit period or never opened their doors to students. The schools had received a total of about $7 million in federal funds. In Florida and California, there was no record of what happened to the equipment, supplies or anything else purchased with the federal dollars for schools that never opened, the audit said.

“We weren’t holding states responsible for monitoring these programs,” Dabby said. “We had to make our standards clear to them in respect to fiscal oversight and also have them thinking very clearly about the quality of education offered to their students.”

The Alliance to Reclaim Our Schools wants the Department of Education to maintain a public database of charter schools that receive federal grants, the students served and the operational and academic performance of each school.

Dabby said the department collects only the names of charter schools that receive federal funds and that states are expected to maintain the other information. She said agency officials have not decided whether to create the public database requested by the alliance.