Sept. 11, 2001, is the haunting presence that permeates "Rescue Me," FX's compelling new series about the members of a New York City firehouse still traumatized by that tragic day when terrorists annihilated the World Trade Center.

Inappropriate though it may sound, TV's first-ever series to use the aftermath of 9/11 as a subplot is primarily a comedy, and not a tasteless one.

Credit series creator and star Denis Leary for this risky but ultimately successful venture, debuting tonight at 10, which marvelously combines dark humor, tragedy and raw human emotion portrayed by its characters.

Even if you are tempted to run for the hills at the mere mention of Leary -- the caustic, cynical and snide comedian -- it's worth considering his tempered performance as Tommy Gavin, the senior member of a fictitious Manhattan firehouse that lost four members on Sept. 11.

Leary portrays Gavin as rough around the edges -- in the opening scene he curses out a class of freshman firefighters -- but the actor also expands his range with a tender side that has rarely been seen in past performances.

Gavin was especially affected by Sept. 11, having lost his cousin and best friend, Jimmy, whose only remains found at Ground Zero consisted of a finger. But Jimmy, portrayed by James McCaffrey, is not just a memory for Gavin, who holds numerous conversations with the ghost of his dead cousin, who eerily sports a bandage around the severed finger. (McCaffrey's previous television credits include guest spots on the "Law & Order" franchises, "New York Undercover" and "Hack.")

The cousin is not the only dead person Gavin sees. He is constantly having visions of victims he tried to save but couldn't, including a little girl who clung to her cat as he carried her out of an apartment fire.

Gavin's domestic life appears to be another casualty. His estranged wife is threatening to move to California with a new boyfriend and take the couple's three kids with her. (He bribes the kids with fives, tens and twenties to extract information about the new man.) She, too, is haunted by the Sept. 11 tragedy, telling Gavin in next week's episode that she can't bear living in a neighborhood where every other house is occupied by a 9/11 widow.

Gavin confides to Jimmy in one of their many conversations that his wife said he was "not emotionally available." In an attempt at self-defense, Gavin tells Jimmy, "Neither are you," but Jimmy responds, "I have an excuse. I'm dead."

Leary wrote the series with Peter Tolan, his co-writer on the short-lived ABC cop show "The Job," and they've come up with some great one-liners.

One of the firefighters inquires to a grizzled veteran about a recent colonoscopy. "Was it uncomfortable -- I mean, the camera?" he asks.

"It wasn't really that camera I minded. It was the crew," the old-timer responds.

The most memorable of the bunch is the beloved station chief, portrayed by Jack McGee, a gambler who will even bet on TV nature shows on whether the lion or hyena will prevail in battle. As he explains it, "I'm a New York City firefighter. My whole life is a goddamn gamble."

The chief reveals a darker side next week, however, when he discovers that a gay firefighter is outing deceased 9/11 colleagues.

Pranks abound in the firehouse mainly at the expense of the new guy Mike, known as the "probie," played by a wide-eyed Michael Lombardi. Tonight, Gavin tells Mike he is required to leave a urine and stool sample on the boss's desk for a hepatitis test. No such test exists.

Less impressive are the show's pyrotechnic effects; tonight's one action scene is nearly indecipherable. No matter. The drama in this series is all in the performances.

The crew of Engine Company 62 is made up of gamblers, womanizers, drinkers and pranksters. Ultimately, "Rescue Me" is less a love letter to the nation's firefighters than a portrait of heroes bonded by the anguish of the past and the fear of the road ahead.

Denis Leary, who created the series, plays a firefighter haunted by the 9/11 disaster on "Rescue Me," debuting tonight at 10 on FX.