A Yonkers Police Department sergeant has gone missing and may be “a danger to himself,” cops said.

Sgt. Robert Byrnes, 48, was last seen Monday in Yonkers, according to a statement from the department.

The officer “has been experiencing recent health problems and may potentially be a danger to himself,” the statement said.

Police have reason to believe Byrnes may currently be in the Far Rockaway Beach area in Queens. 

Byrnes — described as being 5-foot-8 and 140 pounds with light brown hair and blue eyes — was last spotted wearing a brown winter Carhartt-style coat, grey sweatshirt, khaki cargo pants and brown and white wool hat.

Anyone with information about his current whereabouts was asked to contact the Yonkers Police Department at 914 377-7900.