Job changes, life changes, and death are inescapable on Chicago Fire, the long-running firefighter drama that launched NBC’s One Chicago franchise. More than a dozen series regulars have left the show so far, and such exits take a toll, even on the actors.

Former Chicago Fire star Yuriy Sardarov told TV Insider it’s hard to adjust to not being on the call sheet: “You’re on a network television show and waking up every day at 5 a.m. when it’s -20 [degrees],” he said. “You’re outside with your brothers and sisters, carrying a ladder all day and sweating in your suit. Then suddenly to not have that, it’s a real shock to the system.”

Here’s how all the former Chicago Fire stars made their exits — and, for those whose departures were explained, why.