‘NYPD Blue” is ending its 12-season run tonight – not with a bang, but with a tear.

“If this was an ending where a bomb went off in the station house killing all the characters, we’d be really concerned about [revealing] a surprise,” said “Blue” executive producer Bill Clark.

“We’ve had endings in the past that have been real cliffhangers, but this is the end of an era, and it’s not that type of ending,” he said.

“It’s almost as if there was going to be a 13th season.”

Still, ABC didn’t send the “Blue” finale out to TV critics in order to preserve the suspense of what happens tonight.

In the episode, the newly promoted Sipowicz (Dennis Franz, the only remaining original cast member) hunts for a hooker’s killer.

Clark, a retired NYPD detective who’s been with “Blue” since its premiere, said it wasn’t difficult protecting the finale’s contents.

“It was kind of understood,” he said. We didn’t have to shoot phony scripts, as we’ve done in the past when we had some real cliffhangers. This isn’t that.

“I think people are going to be happy just to see it on their own. It’s emotional because of the ride people have had [with the show] the past 12 years.”

The finale represents “another day-in-the-life of the precinct,” series veteran Gordon Clapp (Medavoy) told The Post yesterday.

“It’s a hellish first day on the job for Sipowicz and by the end of it, you’re going, ‘I wonder if he’s going to make it,’ ” he said.

Tonight’s 10 p.m. finale (Ch. 7) will be preceded by a one-hour special, “NYPD Blue: A Final Tribute.”