One construction worker was killed and another injured when a wall collapsed on them at a Lower East Side construction site Monday, police said.

The incident, now under investigation by the city buildings department, took place at 10 a.m. on Norfolk Street at the former site of the Beth Hamedrash Hagadol synagogue, which burned down in 2017.

“We heard the wall collapse. One minute, the two guys were there, the next minute the two guys were gone,” said Tom Daddio, a construction worker who was near the site. “One guy wasn’t moving.”

Witness Robert Kaljha said screams rang out from across the street when the wall fell.

“When it landed, it was kind of really scary, like something landing on a flat surface and a big plot of dust,” Kaljha, 47, said. “Fell in one big piece and just landed, like a clean shot.”

He added, “Coming to work and next thing you know, you have to come home in a bodybag. It’s just ridiculous.”

Video from the scene shows one of the workers being rushed out on a gurney by firefighters and EMS.

One of the men was taken to New York-Presbyterian Hospital, where he was pronounced dead, police said. The other was taken to Bellevue Hospital, where he was listed in stable condition with a leg injury.

Five other workers were at the construction site at 60 Norfolk St., where work began about six months ago to rebuild the synagogue, witnesses said.