CHICAGO (CBS) — The Chicago Police Department is on pace to spend $150 million on overtime this year, which is double the $75 million budgeted.

CBS 2’s Mai Martinez reports that a review of public records show the city has already spent more than $95 million on CPD overtime. And while it can be lucrative for those officers pulling long hours, some who work closely with them fear it’s taking a toll.

Thousands of CPD officers have been volunteering this summer for overtime as part of violence reduction initiates. Others are forced to work weekends and holidays because of cancelled days off. Either way, it has proved profitable for hundreds of officers — many to the tune of tens of thousands of dollars in overtime.

Former Police Supt. Phil Cline said he is not surprised, adding, “When I left, we had 13,500 cops. They’re down to about 12,000 now. Overtime is, I think, the only option they have right now until they get back up to strength.”

A review of city overtime records for more than 8,800 police officers showed some increasing their base salary by more than 70 to 80 percent.

RELATED: Chicago’s Overtime Costs ‘Out Of Control’

For example, one officer with a base salary of about $96,000 earned $77,603.12 in overtime from January 1 to July 31 of this year — more than $17,000 of that was earned in July alone.

Another officer with the same base salary racked up $69,153.20 in overtime for the same period — with more than $16,000 from July.

“Our product is keeping the citizens safe and if you don’t have the cops there to do it, there’s going to be tragic consequences,” Cline said.

The union that represents the majority of CPD officers says the staggering amount of overtime sends a clear message.

“That says that we don’t have enough police officers on this job at this time,” said Patrick Murray, who’s with the Fraternal Order of police (FOP).

And the FOP warns the long hours are taking a physical and emotional toll on some officers.

“There’s officer burnout on this job. It’s probably more apparent on this job than any department in the country,” Murray said. “It’s stress to their families because they can’t go on vacation and they’re notified sometimes that they have to work and it’s not a good situation.”

As for how the city will pay for the additional overtime, in a statement, a spokesperson said, in part, the city will use “existing available revenue and savings and costs reductions in other areas in the city.”