The back-and-forth escalated an already contentious relationship between the mayor and unions.
Emanuel -- who is trying to balance Chicago's budget -- has threatened to lay off 625 city union employees unless what he considers unfairly restrictive and costly work rules are revised.
"Before the day starts, somebody should not get time-and-a-half. They get regular time. Your day hasn't even started," Emanuel said. "I also believe, when it comes to overtime, you should get time-and-a-half, not double-time. These are simple reforms."
"There are about 1,492 or so workers fewer than there were two years ago. So it's an extremely productive work force," said Chicago Federation of Labor President Jorge Ramirez. "If the mayor wants to talk about work rules changes, he's got to do that with the individual unions."
Mayor Emanuel says his reforms would save the city and taxpayers more than $3 million a year.