(CHICAGO) A Cook County Sheriff’s correctional officer was paid $29,467 for a single day’s work last year, according to an audit that says the sheriff needs to better supervise overtime payments.

The officer worked 6.75 hours of overtime on June 15, 2014, but 675 hours were mistakenly entered into the sheriff’s payroll system, the Chicago Sun-Times is reporting.

The officer kept the massive paycheck, but returned the money almost three months later after the error was discovered. The officer, who wasn’t identified in the audit, was disciplined for failing to report the mistake.

In a report released last month, County Auditor Shelly Banks also revealed that 290 correctional officers each received more than $20,000 over an eight-month period in late 2013 and mid-2014. The median salary for a correctional officer is about $61,000, according to sheriff’s officials.

Under a federal consent decree, the sheriff has hired hundreds of additional guards, bringing the total to more than 3,400. Still, the sheriff’s office says it needs to pay overtime to meet required staffing levels in the jail. Most staff shortages stem from unplanned medical time off, according to sheriff’s officials.

About $36 million in overtime was paid to correctional officers in fiscal year 2014, the audit said.

Cara Smith, executive director of the jail, said the sheriff’s office is projecting that overtime will fall to $18.9 million in fiscal 2015 because of reforms in staffing based on recommendations from the audit. She said the sheriff commissioned the audit “to ensure that we appropriate taxpayer dollars as prudently as possible.”

Annie Slezickey, communications director of Teamsters Local 700, said more than $20,000 in overtime pay over eight months isn’t excessive compensation for the correctional officers her union represents.

“What is excessive is the need for overtime because of a failed staffing plan,” she said.

She also agreed with the auditor that the overtime system isn’t adequately maintained.

“Far too often, officers are waiting weeks, months even, to receive their earned overtime pay,” Slezickey said, adding that not all officers have received safety equipment, such as bulletproof vests.

Overtime became an issue this past weekend when 637 correctional officers called in sick over four shifts — more than double the total of previous weekends. Sheriff’s officials suspect the officers were playing hooky to watch the broadcast of the Floyd Mayweather Jr.-Manny Pacquiao fight Saturday in Las Vegas.

But Slezickey called the allegation a “smokescreen.”

She said there are still not enough guards on the payroll to keep the sprawling jail complex safe, and she called Sheriff Tom Dart “a boss who would rather insult them than acknowledge their contributions to public safety.”

The audit, which was presented to the Cook County Board on April 15, recommended Dart tighten controls on overtime payments to prevent future errors or abuse.

In a response, sheriff’s officials said they have beefed up controls on overtime. For example, the sheriff’s “Time Tracker” system now flags any requests for more than 13 hours of overtime a day to prevent another mistaken four- or five-digit payout for a day’s work, according to the office.

Sheriff’s officials told auditors they had created the Time Tracker system internally as a “Band-Aid” while the office waits for the county to launch an automated timekeeping system.

“The continued reliance on a completely manual system to process payroll . . . is susceptible to error,” the sheriff’s office warned auditors.