A tutorial workshop for the upcoming FDNY entrance exam turned raucous last night when the organization that represents black firefighters — which was hosting the Queens event — turned away whites who wanted to attend.

“This is absurd,” fumed Rob, a 21-year-old who was one of about 60 whites refused entry by the Vulcan Society at MS 72 in Jamaica and whose angry reaction drew 30 NYPD cops and school safety officers.

“My dad [a firefighter] was killed on 9/11. I always wanted to be FDNY,” said Rob, who did not give his last name, as about 110 black men received a test prep inside.

But a Vulcan volunteer said he was told to admit people only if they had received a confirmation e-mail from the society, and that the decision had nothing to do with race.

“I wanted everyone to get in, but we don’t have the resources for the amount of people who showed up,” he said. “I understand guys were upset, but then they got a little rowdy.’’

The Vulcan Society and the US Justice Department recently won a lawsuit against the city and the FDNY after a federal judge ruled the department’s hiring practices were discriminatory, and ordered reforms.

Paul Mannix, a deputy FDNY chief who is president of Merit Matters, which opposes the reforms as a watering-down of standards, said that in two earlier workshops this week, the Vulcan Society admitted whites.

“It’s incredible in this day and age” that whites were barred last night, said Mannix, who called the Vulcans’ explanation “disingenuous.’’