A Long Island carnival worker was killed when a spinning ride hit him in the head as he reached underneath it to retrieve something, cops said.

Michael Austin, 22, was knocked to the ground by the Scat ride at the Feast of Mother Cabrini Festival in Brentwood at about 9 p.m. Saturday. He was rushed to a hospital but died early yesterday.

A carnival source said that the ride was filled with passengers but that no other injuries were reported.

Federal and labor authorities said they plan to investigate whether the company behind the festival did anything wrong.

Austin’s relatives could not be reached for comment. The festival is to end today.