A construction worker was seriously injured when he was struck by a falling light pole in Brooklyn on Friday morning, officials and witnesses said.

The unidentified worker was underground doing repair work to a sewer line on East 49th Street across from Kingsbrook Jewish Medical Center about 8:15 a.m. when the pole from an adjacent parking lot came crashing down.

The victim was knocked unconscious from the impact and taken to Kings County Hospital.

It’s unclear what caused the street light to topple, but a worker at the scene said it was accidental.