Richard Mosback didn’t hesitate when he saw his neighbor’s house burning on Astor Drive in Sayville Wednesday afternoon.

He raced over — and found a teenage boy trapped in an upstairs room.

“I could see smoke coming out of the window already on the second floor,” Mosback said.

The smoke was too thick for Mosback to go inside, so the quick-thinking good Samaritan ran back home and grabbed a ladder. With a bystander holding the ladder steady, Mosback climbed up and helped the teenage boy out, just moments before the fire spread.

Mosback recalled the harrowing rescue.

“We got him down. I’m just glad we could get there in time and very shortly thereafter the glass started exploding. And it was a very close call. Very close call,” Mosback said.

Sadly, a dog could not be saved and died in the fire.

Mosback was taken to a hospital and was treated for smoke inhalation.

The teenager he saved did not require medical attention.

The cause of the fire is being investigated. Officials believe it is non-criminal.