LOS ANGELES, Calif.–The city could be overpaying its workers for mileage reimbursements by tens of thousands of dollars per year on average, according to an audit released today.

The audit by City Controller Wendy Greuel raised questions about whether the overpayments are due to paperwork errors and poor oversight or whether workers are stealing taxpayer money.

The city overpaid drivers who use their own vehicles for city business by about $325,000 between 2009 and 2012, according to the audit. The city paid out a total $4.65 million in mileage reimbursements over that period.

In some cases, drivers were paid far in excess of paperwork presented to Greuel’s auditors.

One Bureau of Street Services employee received $30,252 over a 2 1/2-year period, but four mileage statements provided to auditors accounted for only $2,156. Street Services payroll employees were unable to produce an additional 49 mileage statements.

In other cases, drivers understated the distance between their home and headquarters, leading to inflated mileage reimbursements, Greul said.

Greuel said she could not be sure whether overpayments were due to poor paperwork and bad supervisor oversight or to theft. She called the results nonetheless “alarming” and faulted general managers for a lack of attention to detail.

Greuel said the worst offenders were the Street Services and Contract Administration bureaus and the Building and Safety, Housing and Transportation departments, which account for 80 percent of the city’s non-taxable mileage reimbursements.

Bureau of Street Services Director Nazario Saucedo declined to comment on the results of the audit.

Given the city’s tough economic straits, Greuel said the poor management is “absolutely unacceptable and reckless.”

“City leadership cannot tolerate wasteful spending, especially at a time when the city is facing a $230 million budget deficit,” the mayoral hopeful added.

The audit also found that 20 of 52 drivers sampled out of about 1,000 did not have current car insurance policies on file with the city. Fourteen of those sampled did not have a valid driver’s license on file.

Greuel said the missing documents would make the city liable if the drivers got into an accident.

Greuel and City Councilman Dennis Zine, who is running for city controller, said workers who cannot produce valid documents for their mileage reimbursements should pay the amounts back to the city.

Zine said he would introduce a motion when the City Council reconvenes in January to require those workers to pay the money back.

“When they cheat on mileage … and it’s not done in a proper fashion, every taxpayer in the city is victimized,” Zine said.

Greuel called for city department general managers to use more rigid monitoring systems to ensure that mileage being submitted by drivers and subsequent reimbursements are accurate and verifiable.