An early morning Brooklyn apartment fire killed a man and sent two others – including a young boy – to the hospital after firefighters struggled to access a pair of fire hydrants, fire and police officials said.

Authorities responded to a 911 call about a blaze that broke out in a four-story brick building on 80th Street near Fifth Avenue in Bay Ridge at about 3:40 a.m., according to the NYPD.

When cops and firefighters arrived, they found an unconscious 37-year-old man whom EMS rushed to NYU Langone Hospital – Brooklyn.

But the victim did not make it, police said.

Cops also found an injured 34-year-old woman and a 2-year-old boy, and brought them both to the same hospital in stable condition.

FDNY Commissioner Robert Tucker said during a press conference two of the closest fire hydrants were blocked by parked cars, making it harder for firefighters to handle the flames shooting out of the roof.

“I’m begging New Yorkers in all five boroughs: Please do not leave your cars on hydrants,” Tucker said.

“Cars parked [in front of] hydrants are part of the reason we have the outcome that we have here today — this is a fatal fire, and there’s no doubt that the cars that were parked on the hydrants have slowed down our members from engaging in firefighting tactics.”

“Seconds count and when your car’s on a fire hydrant and a fire engine shows up we need to get to that hydrant immediately,” he added. “There’s no time waste working around a parked car.”

The FDNY is investigating the fire’s cause, and the medical examiner will determine the man’s cause of death, cops said.

Authorities have not named the deceased victim, and won’t until his family has been told.

The apartment sits atop the seafood restaurant Mussels & More, which occupies the building’s first floor.