At Cook County Budget hearings this week, Health System CEO John Jay Shannon said nurses account for about two-thirds of the system’s $45 million overtime bill.

He said the system is playing catch-up after a hiring freeze last year—so there aren’t enough nurses to fill every shift with non-OT staff. Shannon said that union contract rules can make the process of filling vacancies cumbersome and that labor shortages make some areas a particular challenge. “Right now, there are not enough operating-room nurses in the world,” he said.