They’re calling it “Graduation, Part 2.”

South Side High School officials announced Monday they will hold a second graduation on Thursday after a sprinkler malfunction caused foul-smelling water to rain on families sitting in one section of Hofstra University’s David S. Mack Sports and Exhibition Complex during the main event last week.

This time, it will be in the Rockville Centre high school’s auditorium.

“It was a freakish occurrence involving the sprinkler system in the arena when we were 15 names from the end of calling students to the stage,” Principal John Murphy said.

The much-anticipated event was going off without a hitch on Friday evening, as it had for years, Murphy recalled.

The arena was adorned with flowers; the graduates processed in their blue caps and gowns.

He stood at the podium giving welcoming remarks.

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At exactly one hour into the ceremony — as he read the name Jourdin Thomas — he looked out at the audience and thought: “Rain must be leaking in from the ceiling” of the 5,023-seat arena.

The wet family members scrambled. A Hofstra building crew was on the scene within 45 seconds.

All 254 graduates and their families — about 1,000 people total — evacuated the arena before those last 15 graduates at the bottom of the alphabet were able to cross the stage and receive their diplomas.

The class president, Paulina Kenny, didn’t get to give her speech.

A student-produced video that was to have accompaniment — for the first time — of a live student orchestra and choir didn’t happen.

And the sea of students in blue were unable to collectively turn their tassels to the other side as graduates of the Class of 2017.

“It will be a great story to tell our children in the future,” said Kenny, 17, who is going on to Cornell University. “I didn’t feel bad about my speech, but for all of the teachers and Mr. Murphy, who worked so hard to make everything perfect for us — I felt bad for them. And for the students who didn’t walk and their families.”

In a statement on the Rockville Centre district’s website, Hofstra University officials apologized for the inconvenience to the educators, graduates and families, calling the situation “unfortunately totally unpredictable.”

The sprinkler system was last tested early this year, officials said.

“The fire alarm was activated by the sprinkler head malfunction, and the burning smell came from water hitting the tops of the lights in the arena,” according to the university’s statement. “The water also had a strong odor which was of concern to the attendees, but we have been assured that while unpleasant, there are no health risks associated with the water discharge from pressurized fire systems.”

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“Again, on behalf of the university we apologize that the malfunction interrupted the celebration of the South Side High School seniors’ great achievement,” the statement said.

Murphy said it is important to hold a ceremony on Thursday for the remaining graduates.

“Graduation, Part 2,” as Murphy and other district officials are calling it, will be held in the 800-seat auditorium at South Side High School at 5 p.m. It will be an abbreviated version featuring those who didn’t get the chance to speak or get their diplomas. It will be an important ceremony to ensure each student gets his and her “moment in the sun,” Murphy said.

“It won’t come close to the grandeur of the real thing, but we are doing our best to make it special,” he added. “It’s about the human dignity of the event, not the whistles and bells.”