Sources told The Post that Rikers Island’s inmate set fire to an infirmary in the jail Friday night, leaving at most three people hurt.

According to the FDNY, the fire broke out on the second floor at Rikers Infirmary Building’s seven-story Rikers building. Nine inmates were housed there. According to a source from the Department of Correction, at least one inmate set it off, according to the source.

“Every individual has been accounted for. There was a small fire at a housing unit at the North Infirmary Command on Rikers Island, which caused heavy smoke conditions,” a DOC spokesperson said in a statement.

The department stated that the flames were under control an hour later with five dozen FDNY personnel responding.

The incident is under investigation.

It is among the most horrific conditions in the jail complex. The Post has exclusive photos that show prisoners sleeping body to body on cells floors that are stained with urine, maggots and rotten foods.

The overcrowded and violent lockup is supposed to close by August 2027 under Mayor Bill de Blasio’s $8.7 billion plan to replace it with smaller jails in every borough except Staten Island by 2026.

Mayor-elect Eric Adams has called for additional reforms at Rikers, and said he will take a closer look at his predecessor’s plan.

“I do support the plan to close Rikers. We have to look at placing of the new jails and make sure the incoming Council persons agree with the locations,” the Democrat said during a debate last month.

Adams called for more prosecutorial funding to speed cases, increased off-site mental and drug health services, and bans against triple shifts for correctional workers.