Two firefighters were hurt and 19 people displaced when a massive blaze ripped through three Bronx homes early Monday, the FDNY said.

Crews responded to the blaze in the row of three-story private dwellings on Harding Avenue near Emerson Avenue just before 1:30 a.m., officials said.

UPS employee James Alvarado, 54, said he was getting ready for work around 1:30 a.m. when he heard an explosion.

“I looked out the kitchen window and saw the glow. Big orange light, glowing,” Alvarado told The Post.

He called 911, grabbed a fire extinguisher and ran out to the backyard, where he saw his neighbor’s fence “already melted from the heat of the flames.”

“All you saw was flames. I had only a small kitchen extinguisher… the flames were just too intense,” Alvarado said.

“I was screaming at the top of my lungs to my neighbors, ‘Fire! Get up, get out! Wake up!'”

When he realized he couldn’t put out the blaze, Alvarado ran back into his home to wake his wife Linda and their Yorkie, Gizmo.

“By the time we came out the whole house was already engulfed in flames,” he said.

The fire reached three alarms, bringing 33 units, with 138 firefighters, to the scene, a department spokesman said.

It was not immediately clear where the fire began, though the initial call came in for 2580 Harding Avenue, where Alvarado lives.

Had he worked his regular shift, which starts a half hour earlier, Alvarado said he would have already been gone by the time the fire broke out, and “I know my wife wouldn’t be here today.”

“I’m convinced I was able to save my wife, my dog and my neighbors,” he said.

“Within 10 minutes it was all engulfed in flames… It’s scary how fast the flames ripped through these homes.”

Two firefighters were taken to local hospitals in unspecified conditions, according to the FDNY.

A dozen adults and seven children were displaced as a result of the fire, which was placed under control just before 3 a.m.

The cause remains under investigation.