In the pilot episode of the show, both Tommy and Lou are wearing the older long style FDNY turnout coats. Denis Leary got the coat he is wearing from the late Capt. Patrick Brown who was the most decorated FDNY firefighter.
Marissa Clark was originally cast as Tommy Gavin's girlfriend, Lauren and filmed the pilot episode, "Guts". After accepting her role on Outback Jack (2004) TBS's reality series set in Australia, the producers could not locate Clark and, panicking, recasting her role.