Judge Valerie Armstrong threw out the charges during a hearing Wednesday. City attorney Robert Tarver Jr. said the city will appeal.
A lawsuit filed on behalf of the girls claims firefighter Richard Williams Jr. persuaded one girl to disrobe and touch his genitals, among other conduct. He is suspended and administrative charges still are pending against him.
Williams has denied any wrongdoing. The Atlantic County Prosecutor's Office declined to file charges because the girls were over 16, the age of consent.
