FDNY Commissioner Daniel Nigro has charged far fewer firefighters with misconduct and substance abuse than his predecessors, data obtained by The Post shows.

Nigro, who has served four years so far under Mayor de Blasio, has filed formal disciplinary charges against 23 firefighters and EMTs. Of those, 10 members fought the charges in administrative trials instead of reaching in-house settlements. Five were fired.

That’s a steep drop from prior Commissioner Salvatore Cassano’s tenure. Over his 3.5 years, he charged 94 members with misconduct, took 21 to trial and fired 16, according to the city’s Office of Administrative Trials and Hearings, or OATH.

Cassano’s predecessor, Nicholas Scoppetta, charged 73 members in the last four years of his eight-year term, brought 25 to trial and terminated 21.

Nigro charged one firefighter, Kevin Simpkins, with testing positive for marijuana, and the administrative law judge recommended termination. Instead, Nigro ended up awarding Simpkins, who had sued the FDNY for leaking information about his case, with a tax-free disability retirement worth about $73,500 a year.

In contrast, Cassano took at least nine firefighters to trial for using illegal drugs.

Nigro has abandoned the “zero-tolerance” drug policy imposed by Scoppetta.

Critics blasted Nigro’s disciplinary about-face in light of recent arrests of firefighters on charges including drunk driving and criminal gun possession.